I would never do this. Even mixing two sodas together would probably taste bad, tbh.
Untrue! Back in elementary school my friends and I drank Sproke (Sprite + Coke) at parties. I haven't had it in forever but I remember it tasting hella good!
I only did this with slushees back when I drank this crap, because the flavours remain segregated. Also we don't really have soda machines in Australia. You get one cup or a bottle and that's it. There's no such thing as free refills, or even paid refills. You just have to buy a new drink. So even if anyone wanted to do this, we couldn't.