Is it even possible to do this in 2025? Thinking about running some old published adventure modules, but I have a couple of players whom I suspect will run to the internet and peek at things only the GM should know. Other than re-writing the adventure myself, can I even guard against this?
It’s not always easy or free to access published material - a lot but not all Adventurers League stuff is on Scribd, and there’s a lot of third-party content on DMsGuild that’s just a little too obscure for liberators to bother de-fingerprinting. If you can’t find a free copy of a title within the first couple pages of web search results then at least you’ve set the bar for spoilers at having to pay for them.
As someone who has played through adventures after having read or even DM’ed them… It’s not hard to take a back seat to other players who don’t know the surprises and twists of an adventure. Encourage your players to make a choice, if they must read ahead then at least don’t trivialize the adventure for the players who don’t.