For sure, the 15 shell limit is total b.s. A guy goes through all that trouble getting on one of those spots, runs through 15 shells and then the spot is vacant the rest of the day. It's not like you can set up a huge snow spread, get your shots, take down and then have another 2-3 groups cycle through there in the same day.
It would be much better for all involved if there was a rule that if you went in the morning you have to leave by noon, no shell limit or at least a reasonable one. With a limit of 20 geese and 7 ducks, 15 shots isn't realistic.