I am installing smoke alarms in my 1930s house. I'd rather not drill into the plaster at this time, but I want to get them mounted. I have drywall beads along the top of all my walls, so I was thinking that I could mount the smoke detectors using some rare-earth magnets. They can hold the weight, but I don't know if the magnets will interfere with the smoke detectors. I've searched around, and it sounds like some smoke detectors can be tested with magnets, but that is it.
Is mounting smoke alarms with magnets going to render the smoke detectors ineffective?
Edit: Thanks for the answers. I'm going to go with a more solid approach, and either find the studs or use an full anchor. Given the importance of fire detection, it's not worth the risk.