[KaVir]

To be honest that doesn't strike me as a particularly constructive feature. If someone has to study or do housework then it's up to them to manage their time appropriately - a self-imposed ban won't stop them from creating a new character, or playing another mud, or going out drinking, etc. It also means that if their situation changes (e.g., they finish their housework earlier than expected) they can't log on.

However I could see it being useful as an indicator for staff or other players, if it provided information about what they were doing and when they expected to be back (a bit like an email autoreply). And if they return before that date, no problem.