OTOH, if you talk about it first, then you forfeit the option to do the sticker thing later, because then the neighbor will know it was you who tampered with device. If you do it like OP did, then the neighbor will not be sure who was responsible, if anyone at all - they might assume they're just imagining things, or not even notice at all, because they're not paying attention. Asking first is a guaranteed way to make them pay attention.

Not advocating any course of action, just gaming out the options a little.