The minhag of not eating gebrochts comes from the fact that there is a chance that there is some flour that didn’t get properly kneaded into the dough and got trapped in an air pocket causing it to stay ‘chametzable’ until it reaches the soup. It is a very unlikely scenario which is why the halocho is that we do not need to worry about it. Never the less, throughout the generations there have always been minhagim that certain communities have adopted to display for themselves the seriousness of chametz – even if they didn’t make so much intellectual sense. (e.g. “don’t put that case of chickens on the floor – my mother was always careful to put it on the counter). Many of these minhagim stuck and the poskim always respected them even if they didn’t practice them themselves.
I, personally, eat gebrochts. But alot of time spent in various matzo factories – both hand and machine – has shown me that the possibility of free flour that hasn’t been properly kneaded or exposed to the high heat is much higher than most people think.
In addition – anyone who does put gebrochts in a utensil of someone who is makpid is probably being oiver on gezel.