Abstraction is a tool that streamlines gameplay.
I see my "dependent on further detail" was well placed. If there's some established situation from which the bandit attack arises through plausible narrative or mechanics, even though that's the first "action!" that occurs, I wouldn't call that the start. The start is the intial framing of the PCs on the road to the remote town, however long or brief that idyllic picture may be.Well, this is an imaginary example, but the thought was that it was an adjudicated outgrowth of the fiction and mechanics. In most games this means it's a twist or consequence presented as a reaction to something like a failed travel or journey roll, or a random encounter roll. It depends on the system. What I was getting at was that it wasn't something the GM just decided should happen.
So yeah, there's a difference in tone and energy between a game that starts with a kicker (whether mooted by players or GM), and one that starts framed more leisurely but jumps to action, and one that starts more leisurely but gradually turns the heat up. Say the players don't run into the bandits, but arrive in town to find people apprehensive and on edge, and only after some investigation do they learn there are bandits on the road that have been causing trouble. Those games are going to feel quite distinct.
!Edit: I usually prefer things like encounters to be an adjudicated reaction to mechanical interaction on the parts of the players, rather than simply a GM decision (or system mandated) roll to see if something happens.