Even with a tight fit, I've experienced cards sliding out during shipment due to high concentrated moisture getting around the packages.. I do not know how this has happened, but I've had a few cards basically "un-tighten" themselves when I first started trading 12 years ago and that is why I've always used tape.
I've even done the whole team bag with a top loader w/o tape to find out people then force cards out of top loaders sometimes with a tight fit to crease them and blame me because they are not careful..
I've gone to strictly taped top loadered cards. You're right, I can always flip the case around to prevent the cards from sticking to tape, but then there is an issue with it banging around in the loader. I've just never had it happen to my knowledge in 11 years that I've done this method (when taping the loader and having the card sleeve facing up right). Just be polite to the other trader and create a flip seam to remove the tape easy, as well as tightly seal the tape to prevent the card from moving around inside the loader with the sleeve. To be honest, I've received so many top loaders that have a pound of crud all over the loader, that I typically reuse them rather than using my fresh ones anymore.
Everyone has their own method, but 'You can please some of the people some of the time, but you cannot please all the people, all of the time'
Zach