Adjusting the coeffecient of elasticity slider can reduce the collision force between bots, but I bet the issue is not a function of bot collisions but rather a function of the default tie length and the default tie "springyness". I haven't changed tie physcis much. The default tie length and "springyness" is that originally specificed by Nums I think when he implemented the new tie physics in the 2.4 fork. Ties when formed have a certain default "springyness" and a certain default length (200 out of 1000 I think). They try to get to their default length so if you fire a tie from a long way away, the acceleration the bot feels as the tie contracts will be large, perhaps snapping the tie.
I'm very open to whatever people want to do on default tie behaviour (I.e. how long their natural length should be set at, how hard ties attempt to acheive their default length, etc.). It's trivial to change this in the code. However, I'd rather not expose it as an option as letting people change this will have a huge impact on how bots behave in different worlds. I'd prefer we agree on a set behavior and hard code it. Bots can always change tie lengths and elasticity themselves, but the default values we need to agree upon....