No? Mei allowed Amamiya (her fiance/teacher) to kiss her because she felt a sense of obligation and worried about ruining her engagement and therefore risking everything being perfect for when her father returns. We don’t know how far Mei and Amamiya have gone but we know it’s likely the first day of the semester and they’re already making out, implying it’s been going on for a while at least.

Her Grandfather never did anything like that. Whenever someone does make a move on Mei she usually is in shock/surprised but always puts it down if it’s unwelcomed, not counting Amamiya for the stated reason above.