To add some...
Tiny baby corns will tend to do tail rattling more than an older snake when startled or going into shed and their vision is poor. It depends on individual temperament, and some may simply bolt away.
They seem to not stress as much as some species, so I can't think of any clear indicators... if you have one go off food, then that would mean something is wrong, but they will often eat under milder stress levels.
Here's a tiny baby corn, in blue/about to shed who was demonstrating defensive/stress signals. Tail was rattling and body held up in a clear strike pose. (I had startled him by lifting his hide and didn't know he had gone blue.. took a picture and put the hide back down right away to leave him be.)
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