That makes no logical or practical sense at all, Th0nt. Even if you are an observer you still don't want to be detected and potentially captured or shot out of the sky. It makes perfect sense to have measures in place to avoid that.If you are an observer, and no threat/passive, then there is no reason to use radar jamming. I also find it impassable that they can part cloak stealth radar yet forget that infra-red or other tools break their cover. Sorry if your that intelligent (as you claim) then its a schoolboy error to not cover other detection techniques with all this tech/intelligence available.
Also, being intelligent and advanced doesn't mean you are perfect or can cover all potential bases with your own technology. It could be that some human technology is too basic to be blockable or they simply don't know (or care) about every single thing we use. Our own rapid advances in techn ology over the last decade may also take them b surprise and leave them unable to counter it quick enough based on observation alone.