I think on boot is probably fine cause I think it might always boot with 1600mhz to prevent booting problems, but I really have no clue if they changed it... But after loading the high memory OC, yeah everything is possible.
I have no Switch experience, but on PC, it's unlikely that you will corrupt the system too because it will crash most likely before it and windows will most likely also auto-protect it self by throwing a BSOD...
But that is all good until.... IT HAPPENS
(even if 1 in a million or more).
On a friend's PC for example I told him to try just 1 step higher frequency without touching voltages and timings, just plug-n-play, all was stable and fine until on 1 3D app somehow it was running massively low performance and he had to go back with stock frequency while all other games and apps he uses was fine.
All kinds of random stuff can happen for sure, though surely I could OC his ram higher if I was there my self increasing voltages, CPU mem controller voltage and messing with timmings, but it was just a quick easy fast OC since he has 0 experience...