People in politics or in a high-contact business who are likely to meet many other people in a superficial fashion don’t say “Nice to meet you.”
They say “Nice to see you,” which is much more neutral. It avoids offending anyone who you might have met before, but without suggesting that this is necessarily a repeat encounter (which “Nice to see you again” would suggest, making the error in the other direction).
I just noticed this recently, and apologize if this is blindingly obvious to anyone who has dealt with people of this stripe…
