The reason I say this is because a drummer can usually spot a drummer. Maybe its in our eyes or something. When I'm playing in a service, and a drummer walks through the door, 9 times out of 10 I can spot him right away.
Mainly because the first thing a drummer usually does when he walks through the door, is quickly spot out where the drums are located. I don't know why that is but it always happens. lol.
But I remember when I was a kid in church, there were 3 of us that hung together. 2 of us are still playing now, but the 3rd never liked drums, he just liked them because the rest of us were interested in them. He wanted to fit in and he didn't want to be the only one who had no interest in drums. So when he asked to play he was never good because he never practiced at home! He never even owned a pair of sticks!
And this is how I know that they aren't serious because if a year goes by, and the kid is banging just as much as he was the previous year, he isn't practicing at home. And the kid who is serious, he has been progressing, and you can hear the difference in his playing.