What InMemoriamSirocco said, except the bit about the heat sinks - if a scan has started they have line of sight so they're not going to help.
The bit about the heat sinks is result of a test run I did yesterday. On my first smuggling run I did not use heatsinks at all, but didn't get successfully scanned, either. One pair of Federal Eagles interdicted me and started to scan. I had submitted, so my ship was able to steer immediately. I turned towards them, boosted past them and thus escaped their line of sight.
Second run I tried the same tactic, only I had been successfully interdicted, leaving my ship unable to steer for valuable seconds. One second after the scan started, all my missions failed. So it was a bugged scan. Insta-Scan.
On my next shadow delivery run I employed two new tactics:
When entering a system, I approached the star into scooping range and then turned my back towards it, filling up on fuel, scanning the system and waiting for the NPCs to spawn. If cops spawned, they most often tried to get behind me and thus got too close to the star, dropping out of SC. I was then able to continue my journey untroubled.
If interdicted, I shot a heatsink and boosted away. Several times a scan started and I remained in front of the cops while boosting away, but my heat signature dropped to 0 % and my canopy froze. I escaped 10 scans that way. None of them finished. I was fired upon, but my Bi-Weave Shields absorbed it and quickly recharged to full strength after the jump.
To the people who call this an exploit: I agree that re-rolling the RNG by switching modes is metagaming. But these missions are the first iteration of engaging mission gameplay that we have had so far.
And why people share information on a forum? Because that is what forums are for. Before Frontier made it possible for one Anaconda to bust the profits on a single trade route, people were happy to share trade route information freely, because they didn't have to be afraid of their own profits diminishing. Those were the glory days of trading, when making profit was a community event. CGs were introduced by Frontier specifically to bring back what they had broken.
I still don't get why Frontier made it possible for a single 500 ton ship to influence the markets of a whole star system. All they achieved was to punish players for sharing trade data. Which is consistent with the "cut-throat galaxy" they are advertising, of course... but a multiplayer game in which everyone plays AGAINST each other and not together with one another is probably not what they had in mind when they decided to make the new Elite an MMO Space Sim.
Just my opinion on the matter.