STICKY 

If a thing is STICKY, it goes home when dropped (See HOMES). If a room 
is STICKY, its drop-to is delayed until the last person leaves (See 
DROP-TOS). Only meaningful for things and rooms.  If a player sets his 
STICKY bit, all pages to him are not permitted, thus the player is 
free from noisy pages, which is useful if someone decides to spam you 
via page. A player's location will also not be displayed in the WHO
list if they are set STICKY (see WHO).