Ok, they're blind for 3.187. I'm sure some reason why they weren't blind will surface shortly after the release of that
Of course, doesn't do much to prevent cheese-scouting via teleport raiders and battlestations, but that's another issue and at least those are not always available.
One point to clarify is that these cheese methods aren't actually "scouting", per se, but rather just getting vision of the planets. Scouting is only done by scouts proper (and eyebots and commandos... hmm, actually commandos could be pretty good at flood-scouting) what is needed to get intel reports and the planet summary, etc.
One way to close off these exploits is to play with an unrevealed map, so only scouts can make the first traversal of any wormhole