I say no. I think there’s too many things which can go wrong in a game especially when money in involved.
Victoria Coren seems to disagree but considers that social rules should be considered up front.
First, you have to decide whether you and your friend are happy to play fully against each other: trap-checking, check-raising, punchy value bets, the lot. If so, don’t be surprised if your friendship turns a little tense for a while. But there is no need to tell everyone your life story. Plenty of casino cohorts know each other and, if you’re playing straight, there’s nothing to announce.
If you are not prepared to treat your friend as any other opponent, you shouldn’t play on the same table. I am still stuck in an ancient tradition with my old mucker The Sweep: if we are heads-up in a casino pot, we check it down. That kind of thing must be announced, but should be avoided. Luckily, The Sweep is a total rock. If he so much as breathes on a pot, I fold everything but aces anyway.
Its getting a little like this when playing Werewolf with friends too.