Tube amps and solid state amps have opposite reactions to load impedances.
In simple designs, solid state amps die almost instantly from shorted outputs. It's so fast and total that almost all solid state amps have designed-in protection from shorts that in turn, they're essentially immune to any load resistance from an open to a short.
Tube output stages can die from high voltage spikes generated when too high a resistance is connected to their output. In simple tube designs, they're almost immune to shorted outputs, but can die from open circuits, or any load resistance above some amount. The exact amount is hard to determine, but open circuit is generally bad for them.
I think the best thing might be to put only NON-shorting output jacks on solid state amps. Tube amps might use dead-short or resistance-connecting jacks. Both would be better than non-shorting jacks for a tube amp.
The problem with speaker cables is that external forces can either short the output cable by squashing it and cutting the insulation, or cut it open entirely, depending on Mother Nature's mood at the moment, and how Her assistant Murphy feels about it.