I've never heard of Dan/Pat snubbing or turning anyone away who asked for an autograph. Everyone I've heard from that's bumped into them said they were very nice.
The trick would be bumping into them. Especially over in Europe, I bet they are very pressed for time trying to get from gig to gig on time and all that.
I don't think they regularly come out before shows to do meet n greet sessions, but if you hang around long enough and put in the time, you just might see them.
When I saw Pat, he was in front of the venue here in Chicago (The Metro) standing outside the tour bus, maybe smoking a cig (I don't remember). Anyhow, I was too nervous to go say hi and bother him but I bet he would have been real cool about it if I did.
I worked in the music business (sorta) at a venue and what I learned about dealing with stars is this - don't be put off if they are too busy to hang out for an hour and chat with you, try to be respectful and they usually go out of their way to let you know how much they appreciate you - but understand that sometimes circumstances don't permit such things, and sometimes let's be honest, everyone gets into a bad mood or has a bad day and doesn't feel like talking. I would bet it's especially tough to be on the road for so long and maintain your cool/patience.
In short, I say go for it! But don't be disappointed if things don't work out. Just let your little guy know that you'll give it a shot and see what happens (that way he won't feel let down). Sorry, I don't mean to give you parenting advice, I don't have children and know jack shit about raising them (although I used to be a kid once).
PS- your kid's got some skills!
"When the power of Love overcomes the love of power, the world will know peace." -Jimi Hendrix
