We don't want to post a specific SC15 code, because then everyone will use that one code, and it'll get killed within weeks.

Instead, search online for "Choice discount code" or something like that, when you have time to go through many pages of results, and you'll find some. They probably won't spell out "SC15" (because that's a term you only see on Choice's website); you're more likely to see "SOS" (Significant Organization Savings), which was the old name for SC15 rates. It used to be that, among other things, you'd get a lot of state and local farm bureaus in such a search. (I don't know if you still do or not.)

Also, I said "5 digit" above, but I now remember than many of the SOS / SC15 codes actually have several leading zeros (which you can leave off when entering the SC15 code on the Choice website).

But sometimes I do get asked (though just casually) about the company/organization that comes up on reservations when I use the SC15 code. (Yes, my checkout folio often does claim I'm from the organization whose SC15 code I used.) So just be prepared to answer reasonably if someone ask you about the company/organization whose SC15 code you used. What you don't want to do is say "I don't know who the hell that is; how did that get on my folio?"!