Watts from head to cab?

[Nubus]

I know that in live sound the amp is rated higher than the speaker to avoid clipping reproduction/speaker detonation. Seems like a lot of guitarist do the other way around. Actually it seems like a lot of people do that. I am starting to think though it may not be much of an issue at all with tube power amps due to the soft characteristics of tube clipping. Am I wrong? Maybe also it isn't an issue because the speaker in a guitar amp rarely reproduces much above say 5 kHz?

[Whoopysnorp]

I think it does have to do with the different nature of tube clipping--I don't think you get the volume spikes that you get with solid state clipping. Plus, since most tube amp users intentionally turn them up to the point of clipping, having the amp be higher power than the speaker would of course blow the speaker.