He could pretend everyone's coming by and keeping him incredibly busy on a day he should be resting because they all adore him. Because they want to be part of a parade of birthday wishes. It's certainly the sort of thing the not-quite-regulars who happen by are going to claim.

Rita assumes. She's clearly here because she had any idea at all it was his birthday. Pure luck had literally nothing to do with it.

Which is why his birthday gift will clearly be her actually volunteering to pay for her own drink. "Little birdie told me you've finally taken the plunge into senility. Say it isn't so."