Nah, I’m messing with you a bit… we do that from time to time (well… I do it pretty much all the time…)
We profess to be purists, and generally try to hold to it (LEGO likes us better if we do), but we allow for some degree of cheating.
Examples:
– Laura has done the copper rails on a bunch of track (honestly, someday we’ll have to make the switch to power functions, but thus far we’ve gotten by with old track and what she’s customized.)
– Ben likes to order third party stuff like mohawks and mushrooms; we’ve allowed this in our displays.
– Tim (and Ben?) has ordered leaves in colors (say, white) LEGO does not provide; I’m not sure whether we’ve used them in displays though.
I think it’s fair to say that third party / custom / aftermarket bricks aren’t as much of an issue as actual competitor’s bricks. If you start using MegaBloks, KREO, or any of that junk, expect endless hazing up to and possibly including excommunication. But stuff like Altbricks is probably OK, for the most part. Unless someone else has a different opinion…