I usually attack some buddies, but not on purpose.... Just because I'm too stupid to remember all their country names. Lol. I try not to.

I think everyone has gotten target tips through viewing ally brigades or watching news to see who gets hit and can't Retal.

I have shared good target ops sometimes with allies in the past, not for many sets though. Don't want to take the chance at a deletion for something so stupid. Usually you end up spying them again to make sure anyways so it really is useless to do since you can already see in your allies brigades what eachother sent. It's not really that advantageous unless it's not your ally your sharing with, or you have someone doing ops directly for you or something. That would be pretty bad.