Being able to go places that people can't normally get to is not the reason Judy's put basically all her magic into being able to teleport. It sure is a neat bonus, though. As is just being able to be places, pretty much instantly, whenever she wants.
Caves are spooky, but less so when you can leave immediately at any time (which is the reason she put basically all her magic into being able to teleport). She fills her jacket pockets with her habitual going-teleporting stash, triple-checks the functionality of her flashlight, walks to one of her usual no-people-no-cameras spots, and disappears.
She doesn't turn on the flashlight immediately, because what's the point of going to a cave if you don't use the opportunity to experience true pitch blackness.
And she stays like that long enough that, when she's suddenly somewhere else, not by her own action, she's blinded as well as stunned.