jeah, you'll puncture real soon. Flats occur mostly on rear tires because you have a better chance to ride around something, thereby avoiding the object with your
front tire. Also, because pf Murphy's Law, the (small but extra) hassle of the cassette & chain come into play with the rear tire. When your tires begin to really show
some wear, the puncture probabliity rises. The rubber is simply thinner & more susceptible to puncture. Around here the usual culprit is the fine sherd of a brown beer bottle.