A little off topic from your question, but last year I went to Pop and I either forgot to do the online check-in or was just too lazy. Either way, it didn't get done lol.
When I got there, there was a HUGE line and I looked at my wife with that "damn it...." look, and slumped on over to the 30+ person line lol. The wife, not being as affected by long lines as I am, looked over and noticed we were on the "Online Check In" line. We both realized we didn't do the online check in, and looked to the left to see 3 people on the normal check in line! I nearly did a backflip over the black dividing strap lol.
Also, as from what I can tell, it seems the check in team is much more willing to give you your little requests if you ask them at the desk when they're just finding your room and putting together your folder. This as compared to when you do the online check in, and another team puts together your Welcome folder and finds your room before you get there. Whether I'm right or not, I have no clue, but that has been my experience w/ asking for requests on pre check-in vs regular check-in. Enjoy your trip!