This is explicitly covered in the original show script. The guards don't usually guard anything. They've obviously taken the weapons out of a locker somewhere for the purpose of guarding Worf.
Scene 4 : ANGLE - WORF
He is sitting alone on a BENCH to one side of the compound, surveying
it. He looks around at the activity in the compound -- a young man is
gardening; a group of young people run and play a game; three men play
a game with dice.
People go about their business, occasionally casting surreptitious
glances at the stranger in their midst. Every time Worf's eye meets
someone else's, they seem to turn away and return to what they were
This place is more a village than a prison -- flowers are planted near
the well tended barracks; the wall that once served to pen prisoners
is still there, but the gate is left open and people come and go at
While there are several generations of Klingons in the camp, the only
Romulans are the middle-aged guards who have been at this post for the
last twenty years. Worf is the first person they've had to guard in a
long time and they have to remind themselves to keep an eye on him and
not be distracted by the goings on in the camp.