Sit out penalty?

so last night at the home game, one of the guys kept sitting out right before his big blind. he’d just say he had to use the bathroom or check a work email or whatever, then jump back in after his blind passed. not everyone noticed but the few that did started getting annoyed, kinda threw off the whole table’s vibe.

i know this gets stricter in online rooms, but what’s the deal for live games? is there like an “unspoken rule” about how many times it’s okay to sit out or skip your blinds? or is this just part of poker and you gotta deal with it? just feels weird, especially in a game that’s supposed to be friendly. do your games have any house rules about this kind of thing?