Well technically you're not protected by the credit card company, they'd drop you like a hot potato given the chance. You're protected by the Consumer Credit Act, which the greasy loan-sharks are obliged to abide by.
Yes, you can get your money back if you don't get the goods/services you paid for, but it takes a while and it's a pain in the ass, red-tape, form-filling nightmare.
The furthest I'd go is buy 10, get 1 free. Certainly wouldn't pay a whole course up-front unless there was a major financial incentive.