Keep that Mic away from speakers!

How many times am I going to see this happen?
Lastnight in Hounslow I was at a family celebration and the Dj was doing a fine job keeping the kids and adults entertained when one of the adults walked right in front of the speaker with the mic turned on and huge feedback click and silence.
Needless to say the amp died instantly and wouldnt even power up afterwards, I felt so sorry for the Dj but this is the second time this year I have witnessed the same thing.
I noticed he had turned the mic gain up when one of the adults was making a speech and was not holding the mic close enough to get a clear signal and he must have forgotten to turn the gain on that mic channel down again .

i dont give the mics out ever.... and if i do for speaches etc the volume gets turned off as soon as they stop speaking.... costly lesson to learn for the dj..... a simple feed back killer like the berry one could of saved his amp..... allso he should have had a spare amp, i allways try to carry 1 spare per amp rack....

I went up to see him after I realised what had happened and he said it was two years old lol, think it was either a citronic 2000 or something like that but it was certainly dead as a dodo. what would have blown in the amp?