Personally, I've never been topped/accosted or whatever the term is by any police officers with or without a PTC. Even the checkpoints only adhere to "looking" only at a vehicle through their windows. I guess they have to present a search warrant to do a "thorough" search.
The only time I was "chased" and asked to pull over by a police car was when they had a report that I was involved in a hit and run incident. They didn't even search my car. After the smoke has cleared, they let me go because I was the wrong car.
I was also apprehended before in a checkpoint because they saw my M4 airsoft gun (I was playing war games then). They said that it could be improvised and I have to explain it to the precinct. The funny thing is that I have my Glock 29 under the seats. Even though they find the Glock I still have a current PTC then.
i guess playing the weakling or innocent can help. the extreme is you can also play the part of a vip. he he he