Could be a number of reasons. Here are the Top Ten:
10) They are Egyptians
09) Sitting in the smoking section
08) Prince has shown up and filled three rows with his body guards.
07) It's the full moon, and you just know that passing the emblems to a Werewolfe doesn't end good.
06) Running out of time, and the program needs to end quickly to accomondate the next group.
05) Nazirites aren't allowed to touch wine
04) Some in that row can only eat Gluton Free
03) There may be ten men in that row holding the skirt of a Jew, Hands are occupied. 02) Chewing gum 01) The row may have their own Wine and Crackers, are are not sharing theirs