i think the guy is fortunate the flywheel did not come out and cause HIM damage,i think the statement of "luck of the draw" and"its just a matter of time" is very poor.Not trying to be an ass here,but any shop that does any kind of work such as that have a "liability".Even if the customer says to take so much off its paper thin,the shop should have had nough sense to say"sorry we cant,,thats gonna make the material way to thin"the guy can come back and sue you even if the guy signed off on it.After a shop lightens a flywheel,it still should never come apart,anyone can machine a flywheel down to nothing and take a pound off it but is it safe?