The only time I have ever worn any letters other than my own was when I was running a campaign for student government and I had the campaign ticket t-shirt on. The top two gals onthe ticket were Sigma Kappas. There was 10 minutes left to vote, and I hadent yet, but couldnt go vote with that t-shirt on. (Campaigning near the voting booth), so the only solution was that the prez candidate gave me her sweatshirt to put over the campaign shirt. Outta respect, I wore it inside out. So you would have trouble seeing the letters. Also I can assure you it was on less than 5 minutes, as it was Sigma Kappa Lavender.
It was wired wearing someone elses letters tho - . I also knew that the gals could get in serious tropuble for letting a guy wear the letters, but I figured it was ok, 'cause they were inside out and 2, it was while trying to help a couple of Sigma Kappas.