The funny part is, beyond freaking people out the first couple times they see her, nothing bad would happen to the population at large, as Sylvie is arguably the nicest person you could get to be Eldritch Abomination, off the top of my head she's losing only to Toki aka Kung Fu Jesus from Fist of the North Star. Both, of course, would lose to Mr.Rogers, if he hadn't allready become a diety.
Of course, Sensei there is going to rolling a lot of SAN checks for the best of reasons, and is also going to need a pelvic cast.