Who on earth would give you an upgrade for "flashing" your ASIC?
Few, if any, check in staff would have the authority to just give someone an upgrade for no good reason.
Except if there is an operational reason, i.e.: economy is over booked and they need to move some people up. Of course, they will choose the more deserving people, like those with a high status, young women traveling solo or with female friends only (seriously, it is the best way to get an upgrade) and those in the industry.
So it would not surprise me if you increase your chances of an operational upgrade by
casually wearing your ASIC. (Don't rub it in or act like you are entitled to it.)