Since getting my PAL a few years ago, I swear every time I cross the border they ask me if I have any firearms... and I don't recall being asked that before I had my PAL... but I just might not remember it happening before. There has never been an issue though... because I would never bring a firearm across the border without the proper paperwork/reason, and I would never try to bring any firearm related merchandise back (like magazines or other 'controlled' items).
I have not noticed any difference since getting my RPAL, crossing the boarder or being pulled over by police. Same old BS IMO