The likelihood for this is very small. The rear is safety bead anyway. Only if your front tire gets completely flat, it may get out of the rim. But before that happens, you will know!!! And what is the difference with tube tire? If you get a puncture, the tire becomes instantaneously instable. At least the tubeless tires will hold much better. First, it is deeper inside the rim, and second it loses air only gradually, and usually you can get back home. I always carry portable inflater, just in case...