No the wording is correct, although it assumes a little bit of background knowledge. You can enable recording ECM's indepently of recording descrambled or not. If you record ECM's with descrambling on, and if for some reason the descrambing failed halfway through the recording, you can descramble the recording afterwards and only the parts where descrambling failed will be descrambled. This has limited use though, because many subscriber cards actively or passively sabotage this scheme. Also a recording with ECM's included triggers enigma to try to decramble it afterwards, which is not always what you want.
So, actually a long story and most people should really leave this to the default "off" position.
Your problem with Eurosport has nothing to do with the actual recording of the ECM pid. I guess it works because the recording ends up with the packets just a little bit farther spread out (because interleaved by ECM packets). Or it might trigger/untrigger a driver bug.