Is this true for all airlines? I looked at CO's terms on an unrestricted (B Class) ticket and it clearly said refundable. If I cancel and refund online, why wouldn't it go right back on the card?
There is no general rule for a B fare. For some routes that is refundable, in others it is non-refundable but with free changes. In others it is refundable but there is a charge for refunds, and it will say "this fare is refundable" but the fare rules clearly say there is a $400 fee for refund for example. I have seen all of these examples buried in pages of complicated fare rules. Note that there isn't even a refundable option on CO.com, just "unrestricted" which doesn't mean refundable necessarily.
Other times airlines change fare rules or make a schedule change that messes up your fare code and changes your rules. If you don't have the old rules saved you might be put into new rules. Etc, etc.
Bottom line-I'm just telling people to realize you're playing with fire here if you don't know exactly what you're doing. For most person returning something to a store will be far simpler.