"Slippery slope," in a sense, only really applies when the slope is steep enough that its slipperiness matters. In particular, there is an obvious difference between "I've discussed problems like this with someone who knows the material" and "I've studied exactly these questions and their answers for the last week."
In the former case, having discussed the material, one is still required to apply one's knowledge in order to produce correct answers on a test. In the latter, one need only reproduce from memory answers one doesn't (necessarily) understand.