Risk using amp Wattage than speaker rating?

YES- You've both gotten the point, precisely. For those customers that came in with toasted tweeters; I gave a little clipping demo and sermon. I also had a little tweeter protection circuit(that I built), comprised of two zener diodes, hot-melt glued into a small round heatsink. When the voltage of the incoming signal(after the high-pass x-over section) exceeded the diode rating, that would go to ground, protecting the tweet. Audibly invisible at normal(below clipping) listening levels.

Patentable!!!

Rtrauthwein,

The wattage rating is the maximum wattage a speaker can handle before they burn out,
and has nothing to do with the Fidelity limit per wattage limit!

30 watts rms is all that most speakers can handle without causing distortion to the audio signal.

Why would you want to drive a speaker at 300 watts any way?

A distortion lesson...

A customer in Holland was having P.A. speakers blown out even when they were operated under the maximum wattage rate.
This speaker was damaged by having the spider separate from the cone after 2-3 days of use.
We did a frequency sweep on a new speaker to see where the cone would put out less acoustic energy.
By plotting the speakers output with a Microphone-amplifier then to a Vdc converter we could see at what frequency the speaker cone was frozen-mechanically due to cone surface aberrations.

That is, one part of the speaker was traveling in a different direction causing, in this case, enough force to rip the voice coil off from the cone. Speaker in use was a 12 inch woofer with 7 inch long slope to the spider.

The mechanics is then: Frequency of ~975 Hz, Feet = 1.17 and inches = 14.01:
7 inches one one side 7 inches up the other side of the cone center
- half of the woofer was going out the other half moving in.

This twisting motion tore the speaker apart at 23 watts input.

Distortion is our point here, anything over 30 watts into a speaker develops distortion, which is far above the Fidelity limits of most Speakers.

100 watt, 300 watts; if you want noise you will get it -
just as long as your speaker does not burn out !

That just sounds like a poorly engineered driver. That thing would tear itself apart eventually even at moderate levels. The main concern in over driving a speaker is exceeding it's X-Max rating.

Sounds more as though they were trying to produce low bass freqs, in a pro environment, with a 12" driver. Too much EQ, too small a driver, and(as Mr C intimated)exceeded it's X-Max. 12" make good mid-bass drivers, in pro applications. 30 Watts is virtually nothing, in a pro setting.