I am not sure if this is a problem that should prompt an architecture change of that caliber. I use a distributed network of GPU-machines and each request is handled sequential. If all machines are busy, then the request goes into a queue already and is being picked up by the first machine that becomes available.
Also, the user got the pictures after just a few minutes and there is a clear disclaimer, and an email is being sent to the user once the pics are ready. On top of that, I have no complaints from other users about it. It's clear to me that the intent of the user was to cause some reputation harm, which I think didn't work. I also got an email from a person with the same first name (not sure if it's the same person tho) that they offer UX services for Headsnap.