I have been doing some protest commitee work and one of the first things we must do is establish if the following rule was complied with.

61.1 Informing the Protestee
(a) A boat intending to protest shall inform the other boat at the first reasonable opportunity. When her protest concerns an incident in the racing area that she is involved in or sees, she shall hail ‘Protest’ and conspicuously display a red flag at the first reasonable opportunity for each. She shall display the flag until she is no longer racing.

I have found that the most effective way to store the protest and penalty flag on the boat is to attach them to the transom lifeline, roll them and cover them with turnbuckle covers. When the flag needs to be flown you simply move the cover to one side and the flag flies – no need for tape etc.