Potowatomi collusion

I don't have much B&M experience but I thought I remember chopping a hand with someone in downtown vegas when we were both all in with the same hand preflop (KK vs. KK) to protect against the chance of one guy catching a flush. I believe i've seen other people do that as well... Any one have a comment on that? In Vegas, I think they pretty much let you do whatever each person involved in the pot agrees on within reason anyway. When I was playing 1/2NL at the Golden Nugget durring the Main Event this year, I remember a guy asking me if I just wanted to take out half of my all-in bet and check it down. The dealer didn't say anything, and I declined the offer anyway. i could be a little off on my memory though... it's happened before