It's not so much a matter of "green". Its really a matter of trichs. In one felt swoop the offender has vaporized every trichome in the bowl. That person enjoys a nicer hash-style high. While every one else has to burn more plant matter to get the same amount of high.

But thats not the way it works cause the offender is there for the second round.
It's like you eating half a banana and handing me the rotted other half. sure its still a banana, but its not as good as the fresh half. then you take a bite of my rotted half, now I'm getting shorted period.