I watched a movie lately, where there was the enemy seemingly appearing out of nowhere and up close already.
I was intrigued to do something like that in Oblivion, but as simple as possible.

Bandits can now appear everywhere in the wilderness, quite close to you already. So watch your steps ;P
They use no spell for this, just a little script.

I also included an update for my Bandit Hunt quest, that includes this feature.

You need to patch this, if you use other mods that do edit the creature leveled lists and/or the bandits. <- Tes4Edit is good or TES4Gecko.
If you use Update1, only the CLVL need patching.