Thanks, I thought i remembered something vaguely like that. But yeah, an adjustment like this is necessary for Dark Sun's exploration/survival pillar to be meaningful at all, and that just can't happen if we're using PHB rules as written. But I don't think that WotC has EVER, in the lifetime of 5th ed, barred or blocked or modified a spell (or feat, or even subclass) for a specific campaign setting. The whole philosophy has been 'the rules are the same everywhere' and 'say yes'. They've made gentle recommendations for canon fidelity in products like Dragonlance, but this isn't really a matter of canonicity or lore which can be debated forever, it's a matter of How To Make Survival Challenging In The World Built Around Survival Being Challenging When You Use The System That Deliberately Provides Several Easy Ways To Stop Survival Being Challenging.