Fourputt
Head Rules Official
I don't see anything wrong with having extra clubs if you are demoing something during a casual round, or even experimenting during a practice round. You just need to make sure you are legal for a tournament.
Or if you are returning scores for handicap.
For a couple of you that are saying a rule is a rule is a rule: Do you always mark each and every ball in the same manner? If you lose a ball on a hole, do you always finish the hole with the same kind of ball?
Having said all that, the most I've ever carried is 13.
Yes I mark the same every time. Just FYI, there is no rule that requires you to use the same kind of ball when substituting a ball under a rule which allows it.