Yup, I have a few pokes that are Trickbanders and it's well useful... the reason I ask is because of this:
http://db.gamefaqs.com/portable/gbadvance/file/pokemon_frlg_moves.txt
"Trickbanding/milking - Using Trick while @ Choice Band, so your opponent gets stuck with the CB. Fairly situational, and it can often work out to your disadvantage if you CB the wrong thing. Not to mention you lose a moveslot. Trickmilking involves Tricking Moomoo Milk onto your opponent. :)"
On the whole it sounds like the FAQ writer knows what he's talking about, so I was confused as to why he would suggest this, and go as far as to give it a nickname (either him or other bot players, anyway)...
frostweaver's explaination makes sence... I guess it could be useful in screwing up an enemy poke who's relying on an item... Still seems pretty pointless :)