I don't bother with cans of spray. By the time they have stung me, it is too late. I know the location, so can steer around it next visit. I try to inform the homeowner of the nest's existence, and leave it to them for a decision regarding action. I make clear that I intend to do nothing. I don't want to attempt to eradicate, fail, and then be blamed for their survival. Most homeowner remedies do fail. Burning the nest out is pretty sure, but spray usually does not do the job. People are different. Some call an exterminator immediately. Others say, "Ho hum, who cares ...?"
I have one widow who has nests in the walls of her house. I have seen bees in/out for the past five years, at least. On hot days, they are really active. They have a hole in a corner. I imagine the walls are filled with combs. The only solution is to start tearing off siding to get to the studs. Since it has gone on for so long, there must be many cavities that are filled with combs. These walls are to the garage, which is not used. I don't know how many penetrate the walls and get into the garage -- never been inside. The location is not near living quarters. The bee entrance is about five feet off the lawn, so I make a quick pass, and hustle on my way. I've never been stung.
Her response: "Should I care?"
Lot of other things around her property are neglected, so neglecting this problem is merely one more entry on the list. I've seen news reports from time to time where a beekeeper is called to a house, a carpenter starts to remove boards, and finds massive combs inside. I imagine this inside wall is similar.