oh I hope I wasn't a part of the attack... lol.
Nah. He was talking about me. Because I've read the rules and I disagree that there must be a meaningful cost to every failure. As it says in the PHB, sometimes when you miss the target DC, you just don't make any progress and the section they quote on cost is specifically talking about activities like ordering a drink.
If you don't allow a retry of knowledge related checks, no progress is bad enough. If you could try forever without using up any resource or risk then don't bother for a call.