Grosjean had to move aside for the lapping car or face a penalty. If the guy behind him can take advantage of that to slip past too then that's cheating in my book. He's gained an unfair advantage from the lapping car - how is that any different to gaining any other unfair advantage, most of which carry penalties?
Personally I want rid of blue flags altogether - let them fight their way past.
Oh he gonna be real mad!
Cheating? No
Exploiting the rules? Yes
Why should he be. The chump should have questioned the decision. I am sure Button wouldn't have made a mistake like that. Lewis maybe fast but he just doesn't have a racing brain what so ever!