Bruh I've been asking myself a similar question. Anyway, Okay, if you're close friends, they might swipe right just because it's funny to do so. You'll have the unserious convos and what not. I wouldn't swipe right just to be polite, either because we're close friends and it'd be as a joke, or because I seriously consider them attractive.
Most Helpful Girl
That happened to me last year. I saw a friend swiped left because i didn't want them to feel uncomfortable... It was the wrong decision though. Well, even though i swiped left and we never connected through tinder, we ended up dating and becoming a couple.
I'd swipe left if I wasn't attracted to them and I'm sure they'd understand. Why put yourself through the potential awkward situation if you don't even like them? Also I never get any matches and I'm sure there are probably others on the same boat as me so eh... like even when I swipe 100% of them right... I still get 0 matches. It's crazy :(