Over time yes, but this says skills were lost during a single session or short term. It was a random group of people, so unknown on what skills they did have before. I think what they observed wasn't a permanent loss, but a placebo effect of having extra help and it was taken away, so for the rest of the test they felt lacking.

My example of calculators was implying one that could do the test work. All calculators have trig functions, and some have calculus abilities. Would a student forget how to find cosine if the calculator was taken away, or do a derivative of a function? Not in one test. But if they were using it first half and then had to do it themselves for the rest, I imagine there's some psychological stuff going on that makes you feel like you've lost that skill.