Yeah, that was way back. Believe it or not, that debate grew out of a problem I had with T4 in my campaign. I switched from MT to T4 when the latter came out, and we had a fairly long campaign using the T4 rules.
I posted my issue on the TML. It blew up into a large discussion (I bet you can find that old discussion in the TML archives--that was back in the early 90's). Marc was on the TML then. Someone, another TML member--not Marc (I've forgotten who), came up with the It's Harder Than I Thought rule. Marc thought it was a good idea and used it as part of the T4.1 task system. He changed a few other things and printed it on the T4 GM's screen.
The rule is now called the This Is Hard rule, as part of the T5 task system.
As Aramis says above, the cautious option actually started with CT when the UTP task system was introduced (DGP's task system for Classic Trav) and naturally became part of MT (because DPG was driving the bus on that edition of the game), then found its way into this current task system.