On the other hand, there aren't billions of dollars to be made in a cottage industry from cranks claiming that fusion-like setups cause things to actually get c

On the other hand, there aren't billions of dollars to be made in a cottage industry from cranks claiming that fusion-like setups cause things to actually get cooler or that some form of reverse-fusion occurs. So if you have enough people looking hard enough and only publishing the best results, you'll definitely get "experiments" which show "anomalous heat". And they will definitely be "hard to reproduce" since they're just noise.