Inna, if your players would rather be TPKed than reap the honest benefits of their actions (the element of surprise), but don't want to be TPKed, I think you may be setting the standards on you a little high.
Also, many of what you're calling 'stealth nerfs' to gather information are actually giving the party more useful information. And as I said, if you want to just give them a map to a place because it does happen to be available in the town, but you want to throw in some complications... gather information is a point at which the party is asking you to tell them random information. Great place to throw it in.
And well, if the information to get directly somewhere is available, expect it might happen.
Reason many of the suggestions have focused on it, is well, it's the example you used, and you've dismissed most of the general suggestions. If you want examples of how to deal with groups using teleport for its intended purpose or groups who start burrowing everywhere or groups who attack someone powerful on a 'gut instinct' they are bad news - those all have their own, individual suggestions. (For that last, I'd advise, if you made the person turn out to be a projected image, be sure this is not an obvious recon.)