Low, since Hermione likely won't remember any creepy stalkers (or the one particular stalker you seem to be thinking of, at least). C&H will continue obliviating her each time until he either succeeds after presenting himself in a way she does not find creepy, which then would be the only encounter she remembers, or gives up.

Now, having made the observation that people are unlikely to talk about things that have been obliviated from their memories, propagate that insight through your belief network in combination with the assumption 'wedrifid is not stupid'. This will hopefully cause an update in your belief "the one particular stalker you seem to be thinking of, at least". I really do refer to stalker after he cleans his (or her) act up. Even once he gets his performance right after n attempts and Hermione listens to him with an open mind he is still someone jumping out of a corridor he had no right to be in giving her personal advice. Harry's stalker(s?) which may or may not be the same as Hermione's stalker is in much the same category.

Even when Harry and Hermione are willing to take interest in what their anonymous advisers are saying they should be comparing notes with each other and finding ways to verify the identity, intentions and reliability of the strangers. It doesn't matter how pretty, charming and respectable he can make himself, he is still a creepy man (or woman) jumping out of corridors, causing unaccounted for fight or flight responses and leaving messages in bedrooms. You don't just keep that sort of thing to yourself. For similar reasons to Harry thinking it would be insane for him to keep the sorting-hat whispering to himself. This is exactly the sort of thing that Harry ridicules.