What does "boardinghouse reach" mean?

Reaching across fellow diners for food instead of asking them to pass it. For example, At holiday meals when the whole family is gathered, Dad always scolds at least one child for his boardinghouse reach. This term alludes to the formerly common boardinghouse practice of seating all the residents at one large table and to the rudeness of those who simply reached across others to help themselves. Heard less often today, it is not quite obsolete. [c. 1900]