Ticket Limits on offers

We've never populated "Limit" when inserting offers. We'd like to create an offer that does enforce a ticket limit. 

My question is, when updating ENFORCE_SEAT_LIMIT_FOR_ORDERS  in "T_Defaults", what happens to existing offers since, when inserting offers, the default on "Limit" is "0"?

If an entry in "Limit" is "0" does it then not enforce any ticket limit?

Just want to be sure I'm not breaking existing offers before I go and update that table. Thanks!