Can you post a photo of the pigtails that you are seeing?
I have a Ridgid ROS (random orbital sander) that I bought at Home Depot. I use Diablo sanding pads in an assortment of grits: 80, 120, 150, 220.
I don't skip grits. I use the weight of the sander and don't press down. I attach the sander to my shop vac to remove dust. I start and stop the sander with the disc on the workpiece. I stop and check my work frequently with a straightedge.
I have not seen pigtails, but I always do a little bit of touch up hand sanding. I use a sanding block, and always sand with the grain. I know that the ROS is "random", so I want to do that last bit of final sanding with the grain. Habit, I suppose.
Could the problem be related to poor dust collection?
For me, the dangers are:
* Not sanding evenly. I keep a straightedge handy as a reference, and check frequently.
* Recognizing that more sanding in a particular spot is not the solution, but I must sand everything else down to match it. It is a variation of the point above.
* Rounding edges when I don't want them rounded.
* Hand sanding without a block. I don't want to leave "finger ripples" (my term) in the wood.
I haven't used the ROS in a while, but I have a red oak wall shelf project in progress, and the next step is sanding with the ROS, so I will pay attention. I may not get to it until later in the week. I will post an update if I learn anything interesting.