Still a nice advantage, if you get close enough. EM flux sensor - if the object stays where it is, you'll get a picture of changing energies. Lifeform analysis - Determine that things are alive on it. If it's not moving, you can even look for life forms or weapons powering up. Given that the Imperials have no specific knowledge of ST technology, it is reasonable to assume that they could not simply jam photon torpedoes.
Lets follow that logic.
Like the Ferengi. Geordi automatically devined what it was and how to stop it. The whole purpose of jamming is to stop them from seeing. Your assertion that they could must be proved. This is a nice train of thought and it in the end dismisses all specualtion that cannot be directly justified.