That's good intel. Was the person being arrested a john or SW?
The information above makes me think of two methods that can be used to cut down the risk:
1. Avoid daytime and stick to late night hours
2. Try to avoid picking up women who are completely isolated and standing far away from other groups.
Most of the real gals are walking to cover ground and catch traffic. I don't know if the UCs can walk around too far because the LEs have to keep an eye on them for their safety.
I believe the UCs try to stay away from the groups because the real gals out there are assessing if some of the other ladies are narcs