Well yes, a trader should always keep up his end of the deal (of respecting redis rules), or else he/she is scamming, and scamming is quite bannable.
PC isn't Smogon, so PC won't enforce redis rules to the extent that Smogon does, blacklist and all; however, I would gladly step in if you happen to be deceived aka scammed while trading with PC members... :P
Although PC does not have redis rules, there are a handful of traders who understand and respect redis rules. If you are into that sort of thing, I recommended only trading with that handful (obvious IV breeders).
Shiny and event collectors do usually redistribute other Pokemon. ^^