YES THEY WILL!!
Funny story - When we brought our first born home, my lovely wife was in dire need of some sleep. So, being the loving husband, I volunteered to take care of our son. Well, the MIL was taking a nap (she stayed for about a week) as was my wife's grandmother, so I am basically all alone with my new son. I hear the little guy start crying and figure it is time for a new diaper (urine on a freshly circumcised winker makes for a mighty unhappy tyke!). So, I put him up on the changing table, pull the old diaper off, clean off the parts with a wipe and, while still holding his legs up, lean down to get a new diaper.
Well, I hear this liquid explosion and he starts cooing (I still think he was laughing at me). Seems he decided to fire off some projectile poop all over the dresser at the end of the table, the changing table itself and the wall on the other side of the dresser while I had lifted him up for the proper trajectory! Well, needless to say, I woke everyone else up with my cries for help, which garners laughs to this day!
Lesson learned the hard way for a new dad - NEVER leave a kid uncovered! NEVER!!! Always cover up until the new diaper is in hand and ready to be put on. Make the switch as fast as humanly possible and whatever you do, don't hold 'em up any longer than necessary. Gives 'em too much time to ponder the possibilities!