The item description says "prevents cargo and weapon scans", but an add-on scanner sees everything equipped, including the scan blocker. Only cargo scan-blocking works.

People really use those scan blockers??? WoW never heard of anyone using them

Mostly because the ships you'd need them the most on, can't use them. Behemoth and Behemoth XC.

It's probably a feature rather than a bug: if I see a moth miner scan as 'Cargo Hold empty, FastCharge battery equipped', I may let it go for a nominal fee. But if it comes back not even showing a power cell equipped, I'm blasting that puppy out of the sky.

Scanner blockers don't make your ship show as empty. They show "Scan blocked" - which right there is going to paint a big fat target on the back of your big fat moth.

Sigh. I shouldn't have given the devs as much credit as I did.

It was originally intended more for NPC convoys. So there might be a big military convoy, but you wouldn't know what was on it prior to attacking.

The scan blocker / spoofer concept definitely needs some work, and some additional addon cases, to make them more useful.

user selectable cargo
chance of success depending on model
chance of success dependant on actual cargo to be hidden
ability to alter ship type
ability to alter pilot id