Do vintage output power tubes - Mullard, Amperex, Telefunken etc - ever red-plate ?

From the Avatar manual:

- A unique circuit has been fitted individually to each of the output EL34 tubes. In the event that an EL34 enters a ’run away’ condition and begins to draw excessive current, the Sentry circuit will engage and limit the current that the tube can draw to approximately 30 milliamperes ( about 60%  of normal )-

Is it enough to prevent big bang in the listening room ?

I once had SED tube red-plated on me right after I turned the amp on.

The Mullards XF2 that I use keep the perfect bias, as far as I can see, and they appear well-matched, in pairs and all four.

@inna 

A tube can red plate for a variety of reasons, none of them having to do with vintage or new production. 

Bad connection on the tube socket, damaged grid stopping resistor, open bias circuit, failed connection in the base of the tube itself, internal short or leakage in the tube. 

I , of course, meant that some vintage tubes might be of such quality that if they ever red-plate it is not because of their failure but because there is something wrong with the amp, and when they do eventually fail they do it differently, not red-plating and exploding.

I understand, most often red-plating happens right after you turn the amp on, though it can happen at any moment.