Me neither, I just wanted to cover all options, no matter how remote.
Why? Fairness does not require pretending that obviously absurd options are on a par with sensible ones. That just undermines any concept of judgment or reason.
As for the possibility of lying: why would they? They have been known to be secretive on some accounts, yes, but they've always maintained they had more advanced technology in some areas than humans did, but simply weren't prepared to disseminate that knowledge (yet) (like warp propulsion, more advanced sensors, etdc). So why would it be different in this case ?
Because you're talking about the
Enterprise era and I'm talking about what we know from centuries later. Once the Vulcans co-founded the Federation, they shared their advanced technology with the other races -- as evidenced by the fact that Earth Starfleet in ENT didn't have the Vulcans' tractor beam technology, but the Federation Starfleet by TOS clearly does. There is no evidence whatsoever to suggest that the Vulcans' secrecy continued
after they became founding members of the Federation.
Besides, by your own argument, T'Pol would've had no reason to attribute the tech to the Tarkaleans rather than just saying outright "Vulcans have this but you're not ready for it."