The conversation about a player activity heat map gave me an idea. Scanners that use energy while active and they scan your surrounding sectors for players and to countermeasure them we should have blockers as well.
I thought it would work like this:

You jump to a sector, let's say the middle of a system and wait to get to 100% energy. Then you press the button and use energy to scan the sectors surrounding you in a circle around your position. Player locations will be displayed as a message in chat but at the same time players that have been scanned also get a notification that their position has been scanned. You could upgrade your scanner/blocker to be more effective. A small port scanner would have the least range, followed by the large port and then perhaps a giant 25 grid version for cap ships. Better scanners use less energy and therefore have more range. Blockers would only block equal or lesser scanners, so a large port blocker blocks small ports and large port scanners but can't defend against capital scanners.
Scanners are unable to scan station sectors and Ion Storms.