**From the words of the Author**  
George R.R. Martin says in [an e-mail correspondence][1]:

>**[Interviewer]** Yet if every knight can create a knight as we have seen in "The Hedge Knight", what prevents a widespread misuse by unscrupulous hedge knights such as Ser Osmynd Kettleblack or the cynical Great Houses?<br />
**[GRRM]** Social pressure. A knight's peers would look with a certain amount of disfavor on anyone who did this. They might gain money, but they would lose honor. And honor is still very important in this culture.

There's more in the interview on the subject, but this is the core of it.

**Repute**  
We know that any knight can make a knight<sup>**1**</sup>, but to make it '**stick**' the knighting knight needs to have the appropriate renown, as explained by the greatest knight of all, [Ser Barristan "The Bold" Selmy][2]:

<sup>[*A Dance With Dragons*:]</sup>
>! As he watched them at their drills, Ser Barristan pondered raising Tumco and Larraq to knighthood then and there, and mayhaps the Red Lamb too. It required a knight to make a knight, and if something should go awry tonight, dawn might find him dead or in a dungeon. Who would dub his squires then? On the other hand, **a young knight’s repute derived at least in part from the honor of the man who conferred knighthood on him**. It would do his lads no good at all if it was known that they were given their spurs by a traitor, and might well land them in the dungeon next to him. They deserve better, Ser Barristan decided. Better a long life as a squire than a short one as a soiled knight.<br /><sup>*-A Song of Ice and Fire: A Dance With Dragons, Part Two - After the Feast (The Kingbreaker).*</sup>

**Examples**  

1. [Ser Duncan The Tall][3] is featured in the novellas *The Dunk and Egg Stories*. Dunk himself has difficulty **proving** his knighthood, but in the end he got **vouched for** by [Prince Baelor "Breakspear" Targaryen][4].
2. Also from *The Dunk and Egg Stories* (*The Mystery Knight*), [Ser Glendon Ball][5] claims that he was knighted in front of many witnesses<sup>**2**</sup>.

**Behaviour**  
A Knight is generally one who is chivalrous and upstanding<sup>**3**</sup> - barring the few who use the title as a means to a gains - this is what sets them apart from normal men (as well as the armor and weaponry.

**We ride spinners**  
A small point which I picked up is that people can almost tell someone is a knight from the horse they ride:

>“Salt pork never pleases me.” The pitchfork knight gave Clegane only the most cursory glance, and paid no attention at all to Arya, but he looked long and hard at Stranger. The stallion was no plow horse, that was plain at a glance. One of the squires almost wound up in the mud when the big black courser bit at his own mount. “How did you come by this beast?” the pitchfork knight demanded.<br />...<br />
“Because knights are fools, and it would have been beneath him to look twice at some poxy peasant.” He gave the horses a lick with the whip. “Keep your eyes down and your tone respectful and say ser a lot, and most knights will never see you. They pay more mind to horses than to smallfolk. He might have known Stranger if he’d ever seen me ride him.”
> <br /><sup>*-A Song of Ice and Fire: A Storm of Swords (Arya).*</sup>

**The talk of the town**  
The fastest way for any news to spread is via gossip. I assume it's not too far-fetched to imagine that the news of a knighting spreads quickly around the realm; imagine something like a bunch of butchers hanging out and chatting among each other "Did you hear that sellsword Bronn got knighted? I saw that the High Septon himself dabbed him and he was dubbed by the Kingsguard!" ... "Wow I need to tell Johnson from Hightower about this!"...

**LMGTFY**  
Unfortunately, there is no possibility of Googling in Westeros, or Essos for that matter, so people can't just go "oh you say you're a knight? let me just check that on the Internet Knighthood DataBase (iKDB) ... Yup, you check out". 

There is however the fact that each Knight and House has a coat of arms, and are therefore distinguishable. These are often recorded in books known as A "Roll of Arms".

<hr />
<sup>
**1.** From *A Dance With Dragons*:

> “Ser Rolly,” said the big man. “Rolly Duckfield. **Any knight can make a knight, and Griff made me**. And you, dwarf?”<br />*-A Song of Ice and Fire: A Dance With Dragons, Part Two - After the Feast (Tyrion).*<br /><br />

</sup>
<sup>
**2.** From *Dunk and Egg Stories, The Mystery Knight*: 

>Half a year ago, however, a party of knights chanced upon the brothel and a certain Ser Morgan Dunstable took a drunken fancy to Ser Glendon's sister. As it happens, the sister was still a virgin and Dunstable did not have the price of her maidenhead. So a bargain was struck. Ser Morgan clubbed her brother a knight, right there in the Pussywillows in front of twenty witnesses, and afterwards little sister took him upstairs and let him pluck her flower. And there you are."<br /><br />
Any knight could make a knight. When he was squiring for Ser Arlan, Dunk had heard tales of other men who'd bought their knighthood with a kindness or a threat or a bag of silver coins, but never with a sister's maiden-head."

<br />
</sup>
<sup>**3.** From the [wiki][6]:
> Knights are supposed to be brave, courageous, honorable, and true to their word. They should be loyal to their feudal overlord, and are tasked with defending their faith. In practice, most knights fall short of sustaining such high and noble ideals. Many do not try particularly hard, and instead seek knighthood mainly for the prestige and opportunities.

<br />
<sup>**4** See this conversation between Dunk and Egg:
>"Do you want a clout in the ear? What book is that?" Dunk saw bright colors on the page, little painted shields hiding in amongst the letters.<br />
"A roll of arms, ser."<br />
"Looking for the Fiddler? You won't find him. They don't put hedge knights in those rolls, just lords and champions."<br />*-Dunk and Egg Stories, The Mystery Knight*
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  [1]: http://www.westeros.org/Citadel/SSM/Entry/1045
  [2]: http://awoiaf.westeros.org/index.php/Barristan_Selmy
  [3]: http://awoiaf.westeros.org/index.php/Dunk
  [4]: http://awoiaf.westeros.org/index.php/Baelor_Targaryen
  [5]: http://awoiaf.westeros.org/index.php/Glendon_Flowers
  [6]: http://awoiaf.westeros.org/index.php/Knight