I've been searching the forum on this topic for some time, but I'm still confused. Do listen/spot work only on random encounters with survival? (In this case I need only one PC with these skills?) Somewhere I read they are used in "surprise" rounds - they do exist in toee?
I'd say yes, millions wouldn't. You'll notice sometimes when you initiate combat that you get a crack and only some monsters are in the melee thing, sometimes it's because they haven't figured out there is a combat yet but some get added after you - meaning they will get a go that round - and some are added before you (meaning they have missed their go that round). So I would say it's a surprise round based on individual initiative rather than a group round. Spot and listen will also determine whether the monsters see you when sneaking. For PCs, probably there is very little use other than - random encounters as you say - specific scripted moments like Furnok cheating at cards, Dala robbing you etc. - no idea if they affect initiative and/or surprise rounds - very interesting if they do.
Calling that a surprise round is a bit of a stretch. There's actually some vestigial engine code for surprise rounds, but it doesn't have any actual effect.
