My house rules stay in my house , or at least within the small group of friends who tweaked or developed what ever rule it is. I'm happy to share and exchange house rules and tweaks with close friends. However, when I'm out of my own home, like at game club, or a con, I expect to play a game by the standard rules, or at least by a well known and accepted variant that is in the rule book. The simple reason for this is that these are the rules everyone knows.
I used to be more open to house rules, but experience has now taught me that the fastest way to misery at the game table is to allow someone's home brew to take over. It is awkward enough to be playing games with people who you may not know well. It's even more awkward when everyone realizes a few turns into the game that everyone is playing by their own rules. Best case scenario, the dominate player pushes their rules on the meeker or more polite players, worst case scenario, you end up in a protracted argument discussion about the rules. Someone always ends up feeling put out.
Several months ago, after enduring yet another rather disappointing evening as the result of politely conceding to play by the game owner's rules, rather than by the game designer's rules, I decided that I simply will no longer play games that are prone to house rules with the general gaming public. Arkham Horror is at the top of this list, along with Talisman.