the trigger shoe for the P-11 is more narrow than the trigger guard, so it is still protected.
ANY gun in ANY holster should first be checked for fit while unloaded, as MANY good holsters use the trigger guard area to retain the pistol. What you must check for is if the holster contacts the trigger (stock width or with the shoe).
it is far more likely for something to get in front of the trigger while holstering (like a finger, or the retention snap) and pull it (which would not be affected by the shoe).
With the P-11 there is are draw backs with the shoe in that many have had them come loose if just held on with the set screws. Also you have to remove the shoe to take the frame out of the grip. These can be solved by widening the hole in the grip (so the trigger can come out with the shoe) and permanatly attaching the shoe to the trigger (I used JB-Weld).
Also remember the trigger is a $.50 part, if I want to remove the shoe, I'll buy another trigger....