For sure there are at least as many answers to these types of questions as there are folks tossing critter parts into smoke. And maybe more because after a while we all seem to have our "but on the other hand...." kinds of thoughts.
For me, no mopping, no foiling, no spritzing of anything. Not pork, beef, poultry, venison-nothing. And it doesn't matter if I'm smoking over an electric burner, charcoal or wood. But that's my choice.
When making pulled pork however I do however usually remove butts when they are about half done and finish them in a roasting pan in the oven or smoker. The goal there is to save the juices, de-fat them and add as much back to the shredded pork as will absorb to boost the pork flavor and moistness. It really cuts down on the amount of sauce folks use (often they opt for no sauce) and folks rave about the depth of the pork flavor.....who knew? Pulled pork is supposed to taste like pork and not smokey sauce? So I guess that while I'm not, strictly speaking, foiling the butt it is somewhat the same idea.
Best regards to all