Do any of you go boot-less (Sport boots) when running in the mud? 

I don't.  For the simple fact that is when they have a higher change of slip,trip, fall, which could lead to them doing all sorts of things.  I prefer the protection and stuff will wash.  It's not ideal, because the stuff can be somewhat heavier, but I'd rather have the stuff covering sensitive leg skin and tendons than slicing them on an oops. 

It depends on how deep the mud is and  what kind of suction and sticky you are looking at.  If the boots are going to contribute to making the conditions worse I pull them.  I always use bell boots though.

I never did, always ran with them, they really need the extra protection in mud since the mud can cause them to displace their movement. I rather have that protection.

I've been using polo wraps more than anything lately... I think I'd still use then if I was running in the mud. Be real easy to just toss them in the wash. I have stock in oxy-clean anyway... 2 boys that play baseball and it's always white pants ... always..... white...... pants!!! 

I like the old Galemba leather boots, the ones with buckles not velcro.  They don't get heavy in the mud or wet, especially if you put a leather conditioner/ waterproofer on them, and the buckles don't come undone.

Man I really miss the days when my boys would come home covered in mud after a day of dirt bikes and playing in the Orange Groves while irrigating the orchards behind our house. Time just gos by to fast when your kids are being kids.