EHG certainly IS headling, yet I must say that I don't care of such thing and most of all, I would prefer NOT to "headline" anywhere. Especially not in fests. I don't know is it Finnish phenomena, or just type of people I know, but most people I know basically compete who can play sooner than the others, hah!
It's not really order of bands what defines "headliner". Seen so many gigs where the good band plays, and half of audience leaves after that, leaving "headliner(s)" to play for half empty venue. In this EHG gig, there's no worry of that. It's good live band that always delivers! Seen them few times in Finland & Estonia.