I always thought the “waitress is practicing politics” meant she had to keep the men interested enough to leave big tips without actually encouraging them to complete the passes they keep making at her.
I thought it was sort of a double entendre. She’s “practicing politics” by trying to ward off advances but not discourage tips and she’s probably a law or poly-sci student.
I’ve always wondered about the odd internal rhyme scheme of the verses. The first verse is line seven (But it’s sad and it’s sweeet/And I knew it complete). The second and third are line three (And he’s quick with a joke/or a light of your smoke; And he’s talking to Davy/Who’s still in the Navy), and the last verse has them at both three and seven (Cause he knows that it’s me, they’ve been coming to see; And they sit at the bar/And put bread in my jar).