It is too easy to go into DND and sometimes not realise it.
It would be better if to enter DND mode you had to hold the button for 2-3sec so that it is difficult to do this by accident.

Perhaps a site-wide configuration parameter that "unsets" the DND function after a specified period of time.
Suggestions were 15, 30, 45, 60? Perhaps a profile setting like sleep on an alarm clock could be set by the user on the badge?