I was designing a gadget and wanted to include some ECM capability but couldn't work out what trait would be needed for this. So I've created the following new trait:
Block Scan is a Minor Good Gadget Trait that interferes with use of the Scan trait – it is intended to represent Electronic Counter-Measures or similar. Similar to the Scan trait, when Block Scan is purchased it must be nominated to work against either “general scanning” or “specific scanning”. If chosen to block general scanning, it provides a -2 penalty on any Scan roll directed against whatever Block Scan is protecting. If chosen to block specific scanning, it provides a -3 penalty on the specific type of Scan only and -1 against other types of Scan.
Block Scan can be purchased multiple times and these penalties are then cumulative.
I didn't see that in the Traits listed in the GM's Guide, but yes I suppose it would. Difference being that this trait would block scans as well (like the Dalek fleet did in Bad Wolf/Parting of the Ways), whereas plain ol' invisibility would leave you vulnerable to everything except the naked eye.
Personally, I'd prefer to keep Block Scan as a separate trait and if you want to have the gadget also effective against vision, then buy Invisibility on top. A Major version of Block Scan would be unbalanced in comparison to Invisibility, as Block Scan would then cover both Invisibility (Major) and Block Scan (Minor) but at the same cost as Invisibility (Major) only - who would then buy Invisibility?
(Alternatively, you could have a Special level of Block Scan which combines the effects of the Minor Block Scan and Major Invisibility, and costs 3 points.)