Can I really put frozen ramekins in a preheated oven? I found a make-ahead chocolate souffle recipe that calls for freezing prepared ramekins and then pulling them out (without thawing) and baking in a preheated 400F oven. Isn't that a bad idea, risking cracking the ramekins from the thermal stress?

The recipe is originally from America's Test Kitchen (paywalled, sorry), so I'd expect it to be pretty trustworthy, but this seems a bit scary!
I wouldn't worry about it too much -- those cold ramekins are still going to heat up relatively slowly over minutes. 

Dunking super hot ramekins into cold water, on the other hand, will cool them down in a matter of seconds which is where you're more likely to experience catastrophic thermal shock.