We paid for our Rosh Hashana seats, and when my son came to sit down, found it occupied by someone who did NOT pay for it (we have a seating chart, and the person was not even supposed to be in that row). My son made no comment, found himself another seat, by checking the chart for availability, and made certain to come early enough the next day to sit in his paid-for seat. The other person came back the next day and sat somewhere else when he saw the seat was already occupied.
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