If you put a character to bed, or if they lie down on stray clothing, they will not respond to shift changes or needs unless manually woken up.
There should be interrupts to sleep on changes to shift states (eg, going from sleep/free to work time) and limits to how long naps last.
They will also not wake up to tend to needs that have reached a critical state (food, drink, hygiene, toilet) and will not wake up in critical changes to their environment (breaches, unsafe temps)