From what I understand (and others have posted here about being harassed by LE) with just about all the low end motels they are looking for drugs not prostitution. So if you go there maybe park somewhere else and walk (I used to park in Walmart lot when I used to go to the Americana - so they could search me but not my car).
If you feel the need to park in the motel lot (or perhaps the girl wants to see your car drive up before she gives you the room #) just make sure everything is up to date on your car (inspec sticker, reg's, good tires, all lights working, etc) and above all do not have anything illegal in your car or on your person. Don't even think about parking in lot if you have a suspended license or a pile of unpaid parking tickets.