Yes they do - 30 seconds.
Actually (more seriously), there is wiggle room in the "reasonable time" clause, and you could always tell the group if they are cold-hearted "I'm hitting the head and will be late to the tee. Give me an Excessive Time warning when I get back if you want."
801.03 Excessive Time:
A. A maximum of 30 seconds is allowed to each player to make a throw after:
(1) the previous player has thrown; and,
(2) the player has taken a reasonable time to arrive at the disc and mark the lie; and,
(3) the playing area is clear and free of distractions.
B. A player shall receive a warning for the first excessive time violation if observed by two or more players of the group or an official. The player shall be assessed one penalty throw for each subsequent excessive time violation in the same round if observed by two or more players of the group or an official.