Probably yes, but also probably the person who would check for this kind of thing was probably let go already :P

You can “help” your friend who is bootstrapping his startup. You can even book a room in the office and meet with your friend there. As long as you are available for work in the office, it can count as “training”. Just don’t be blatant about it. Like, reserve rooms on a different floor every day. Or I imagine that is how it would be done, I definitely didn’t do this when I was benched on this big company for months.