Risk using amp Wattage than speaker 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.

Having repaired speaker systems for a couple decades; I can assure you that high powered amps can damage low power rated systems. Crossover capacitors are rated for only so many volts, and lots of manufacturers skimp there. I've lost count of how many aluminum electrolytics(cheap/cheap) I've seen popped like firecrackers. The drivers themselves(cone or dome type) can EASILY exceed their maximum linear excursion range and either bottom(and crush) the voicecoil, or destroy it on the top edge of the magnet structure. Then there is the ubiquitous fried/overpowered voice coil, caused by more wattage than the driver was designed for. Overdriving an amp causes clipping(very high freq distortion- resembles a square wave on an O-scope), which a crossover network will pass first to the tweeter, and toast it. Owning a shoppe in Winter Park(FL), surrounded by over eighteen college campuses, and a plethora of live(and canned) music venues; I saw LOTS of damage caused by overpowering. However; I would estimate the clipping damage(tweeter replacements) to have been twice as high(post traumatic college party syndrome). I always recommended a higher powered amp as safer, and cleaner sounding, for any given system.

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.