Ummm... TV tubes like arcade tubes have a VERY VERY thick front part of the tube. The glass is over 1" thick solid, and why the tube weighs so much and the center of gravity is only about 1.5" back from the front of the tube. The rest of the tube has glass as thin as 1/8" around the neck.
Anyway, if you break the glass on the tube at the neck the usual thing that happens is you will let air in and ruin the tube (let the vacuum out as it were). However if a crack/hit occurs on the side or especially front of the tube, you can expect a serious implosion followed by expulsion of glass, phosphorus, lead and other nefarious materials outward in all directions up to 20 feet.
That said... the most a CRT can have is a SCRATCH on the face of the tube. A crack would lead to immediate implosion due to the high amount of vacuum in the tube as well as the very tight metal band compressing the tube around the front edge.
Most of the "flat screen" TV's simply have an extra piece of glass immediately in front of the tube. Tubes can be made much flatter now days but even some cheap tvs (e.g. apex) use round tubes and a flat front to make them appear "true flat".