PP-amp with no load

[soundbrigade]

It is wellknown that pushpull amplifiers disintegrate when powered up without a load. No load equals infinite load impedance, which transformers itself to yet a higher load impedance to the anodes of the output tubes. The situation with infinite load impedance often leads to a situation where the slightest imperfection or lack of balance triggers an oscillation that rapidly takes out the tubes and often the transformer.
But what happens if the transformer is loading the tubes on the cathode side? Will the same happen?

Typical circlotron, that's waht this kind of amplifier is called:

[dcriner]

I wonder if this concern is always true? I have inadvertently disconnected the load from p-p amps, without damage. I haven't been in this particular situation, but what if the amp has two sets of speakers, and an A-B selector switch?