All extra rest stop camps would do would be to increase the number of homeless in camps.  Based on your logic, each one would increase the odds of more violent people showing up to be in them.

Whether it is 1 per 100 or 2 per 100, each additional 100 'homeless' would increase the actual number of violent people coming in.

The 'housed' number of violent people would be stable; the number of 'homeless" violent people would be proportional to those invited to stop at the 'rest stops.

Why do we want to invite any more homeless people, violent or not?