I don't like the idea of being forced into quests in Elder Scrolls games. For me that's one of the great things that makes the series unique.
Call me boring, but often I just like to wander around and take in the world. Being suddenly thrown into a quest when i'm exploring would just irritate me a lot. I got annoyed enough with creatures constantly attacking me and triggering the battle music in Oblivion that I went around in 100% chameleon a lot of the time just so I could wander undisturbed.
Besides, I think something like walking into a trap in the wild and being thrown into a related quest to escape would feel very scripted and would actually have a negative effect on immersion.
It would have a negative effect because it took you away from wandering around taking in the world? I dont that walking into a trap/being captured or whatever you like and in turn being forced to escape or fight your way out would feel scripted, what other options would you want to have, wait for them to kill you?
You compare being thrown into a quest with monsters being placed throughout the world that annoy you when they attack you, would you rather have an empty landscape with no posibility or risk of anything happening?
ALTHOUGH i do agree with you in that it would work well if it happened maybe once throughout the entire playthrough, possibly not happening at all in the second playthrough.