Hi there,
Sounds like an excuse to me, but maybe I'm just being negative. Most of our traffic comes from CL. The crimes I've heard involving CL are from someone buying/selling cars or other items. Perhaps if you give them a reality check that, while it's always possible, it's not probable that someone from CL is going to come to a property - where there are numerous people milling about - to do them harm. You may want to call some surrounding managers and ask how many tours they have had in the last quarter from CL and if there have been any problems (I'm sure the answer will be no). Then talk to the staff about it and let them know that it is their job to show units from all sources of traffic (you get photo ID's, right?). It sounds like you've worked with them as much as you can, and forcing them to do their job may be your only route. You may want to throw in an additional safety training. I wouldn't be surprised if there is one person leading that charge and feeding the paranoia to the others. Good luck!