I'm not sure my experience is typical. In recent years at least, the problem, when gaming in the evening after work, was keeping players from lapsing into a comatose state, rather than dropping to player level. Caffeine has little effect on the habituated. Worse, when players were out of the limelight, multi-tasking happens as people took to maximizing the use of their free time (reading, checking e-mail on laptops), to the extent of needing to prod people when their PCs' actions came round in combat.
At that point a simple “Your turn” and a pause for context-switching sufficed.
No-one violated character, but were active only fleetingly.