Wellllllllllllllllll... lemme weigh in here on this discussion.
Quite honestly, you're ALL boiling your ribs, with or without foil, with the exception of AZRocker and his friend Mike Miller.
The composition of meat is that of individual cells. Each cell contains liquid. If you freeze meat, frozen liquid expands. When it expands, it bursts the cell wall. When it unthaws, you see it on your table instead of staying inside the meat. That is why previously frozen meat is dry, such as turkey (why a fresh turkey is always more moist than a frozen one).
The same holds true for the opposite end... cooking. If you cook meat at a temperature higher than the boiling point of liquid (based on your altitude), then the liquid inside each cell will boil, burst the cell wall and boil out of your meat. Regardless of the cooking method - wet, dry, foiled, not foiled, whatever. Only by keeping the temperature below the boiling point will the liquid inside each cell NOT boil. If you're smoking at 220°, at some point that liquid will equalize with that temperature and boil. Now, that's not saying that the meat itself is reaching that temperature; it can be considerably lower; just the moisture inside the cell is. A good example of how that can happen is if you microwave a piece of apple pie with a scoop of ice cream on top. You can get the liquid in the apple pie sauce to get steaming hot without melting the ice cream hardly at all and just barely warming the piecrust. Although smoking is not microwaving, you're still irradiating the meat and the temperature of the liquid will rise much faster than of the solid.
This is why I don't cook a prime rib at anything higher than 200° in the oven at Christmastime. I don't want to boil out the liquid out of the meat; I'd rather have it be retained until I cut into it, then capture as much as possible from the broken cells that my knife created parting it. And, as they say, the proof is in the pudding.... here's some 'rib shots':Christmas '05Christmas '07 - had grandkids by then, a lot more pics of them than of the meat! lol!The liquid stayed in the meat instead of ending up in the bottom of the pan -we barely had enough juice for gravy. You could press down on the meat and it would leak juice it retained it so well.