Anecdotal, but I’ve never once had a problem with any function of Firefox in the decade I’ve been using it. On the contrary it’s been the most stable browser I’ve had the pleasure of using, orders of magnitude more reliable in all situations than Chrome or Opera ever was.
This post smells of astroturfing. There’s been an awful lot of “why is Firefox so shit?” posts recently, now that Google is proving itself untrustable.
They will trigger a laser alarm though. Depends what type of fire alarm you have. I have a laser alarm in my house and if I open the bathroom door too quick after a shower the steam can even trigger it.