Replying to the comment "I wish Cozumel dive ops would require all divers to carry a SMB. If they don't have their own, the dive op should have loaners on the boat to provide to them."Yes defo good idea....
If one doesn't have an SMB and practiced deploying it I would not advise trying to inflate a loaner buoy except at the surface. Loaner SMBs should probably not have a reel or spool attached.