Almost everyone in this thread is retarded. The message doesn't say you can't do that, it just advises you not to.
Steam cannot ban you for refunding as certain places have that codified as a consumer right and it's not against ToS either.
Steam gives you that message because they don't want you to keep refunding shit because it costs them money to process all of that, especially if you refund to CC but they can't really prevent you from doing that outside of asking you politely.
The only way you'll ever get banned on Steam is CC fraud or selling your account. Even if you spam the most offensive shit imaginable you'll just get community banned and even then it's not easy to do. Cheating in VAC games just bans you from VAC games (online). They won't even ban you for using Steamworks for pirated bans. They didn't ban anyone exploiting Steam points back in the day either.
And no it's not Valve being benevolent, they simply understand that you make way more money by not upsetting your consumers.