So what's your view on blue flags?

I've been hearing a lot of complaints about how they spoil racing, that leaders should just overtake the drivers in front and yadda yadda. On top of that, now you have Gunther Steiner claiming somewhere that F1 should get rid of blue flags altogether.

Personally, my opinion is that blue flags are just fine and that penalties like the one Grosjean got in Singapore are perfect, for two reasons:

1) If you think that spoiling a fight for 9th place is an issue, try to think of the huge amount of moaning that we'd got had Hamilton lost his Singapore win owing to Grosjean blocking him.
2) This opens the door for A LOT of dirty play, particularly with B teams. For instance, what would stop a Toro Rosso driver from letting the Red Bulls past, but blocking everyone else? Or what if Räikkönen was having a bad race and Ferrari gave him an extra stop so that he'd emerge right in front of Hamilton just to make him lose time in (trying to) overtake?