Whoa, Zen's a player. Well, he is compared to me; I had all of one girlfriend while I was in public school. No regrets, though; I think I was better off, anyway.
As for today's Kogasa-san comic, that sure looked like it could have been a date. I do hang out with love interests in a non-romantic fashion all the time, though, so it doesn't have to be a date. I would still tread carefully with telling any of that to Sanae-san, though.