can I 'patch in' a bathroom vent into my kitchen's stove hood vent?
those came across my mind, but I figured there's gotta be a way around it (gaskets that open only when on or something? Like you wouldn't smell a dump in the kitchen because the kitchen's vent isn't 'open' unless the unit's on and blowing outside).
I'm of the same mindset, when something feels like a shortcut, I always feel it's not the right way. But this is a situation where if I don't put a bathroom fan in this way, I won't be putting one in at all (until I feel comfortable enough to redo my roof, but that's not gonna be for many, many months, if not over a year). So if there is a way to do it that isn't a bad way, just an unusual way (but a way that won't cause any problems - a method that's just weird, maybe inefficient, harder to setup, but won't cause any problems), I'm all for it.