I remember someone talking about a pro who had 34/53 or 34/56 for one of the mountain stages.
most double FD are rated for 14-16t difference. I'm sure it's no big deal, the specs on the paper are just guidelines so that the manufacturers don't get sued from people installing things incorrectly.

at worst when you have a 34/53 you may have to get a triple FD since those are rated at max 20t difference.