In Star Wars Episode Five, during the Battle of Hoth, numerous AT-ATs' legs were tied up by snowspeeders. From what I understand, this was a new tactic that was invented on the spot by Luke Skywalker after conventional methods to bring the walkers down (primarly lasers from the bases turrets and the speeders themselves) failed to damage the heavy armor plating. This being said, it seems as if the walker captains had no little to no knowledge of what was actually going on. Were there no hydraulic feedback mechanisms between the legs and the dashboard that would alert the pilots of the issue? Did other walker captains not understand what the rebels were trying to do? Did they just fail to communicate with the "lassoed" walker's captains to tell him to stop walking forward? Or did they underestimate the strength of the cables? Strategically speaking, the least they could have done is remain stationary and provide support from afar. Numerous possibilites come to my mind regarding this issue. But for multiple walkers to go down due to a perfectly avoidable tactic seems like a collective failure on the part of the ground forces. Was there something else going on that viewers didn't know about?
First of all, chances are the walker crew likely would not have known how they were brought down. They just came crashing down suddenly. Although there would have been some feedback (likely) between legs and body, there wasn't really an indication of what that was. We, as the viewers, knew... but it happened so quickly. Suddenly, the crew were thrust forward into the ground. Not long after, another speeder blasts them.
Even if they would have had time to relay the message to other walkers, chances are in the heat of the battle that they wouldn't have known what the cause was.
2nd of all, the walkers had to keep advancing. The walkers were their main tactical advantage on the open plain of the snowfield. What other options did they have? Chances are the AT-ATs were used on a variety of planets and that's what was on hand.
They had to keep advancing to get close enough to disable the shield generators. They were, essentially, expendable, as long as they accomplished their mission.
From a Physics perspective they couldn't stop even if they knew exactly what had happened.
Try walking when someone has tied your shoes together... or running and hitting a wire etc, you fall.
It's very hard for anything on 2 or 4 legs to "stop on a dime". The forward momentum is always going to continue in some way. If they tried to stop the outcome would be the same as the fall that occurred, the Walker would fall the same way, the movie shows the leg trying to move as a cue, but even if they tried stopping it would still move until the system could kick in to stop it. A vehicle that size on 4 legs would practically have to do a "military stop", one final step and a final foot plant to kill the momentum.