It depends on the restaurant. I think they say that so that you won't be upset if they cannot sit you all together due to lack of available adjacent tables. However, I talked with someone at DDR yesterday and it also depends on the kind of seating available at the restaurant. Some restaurants have rounds, which make it impossible for them to push the tables together to make one large table for a big party. Most restaurants do have enough square or rectangular tables to allow them to do this, but that does impact your ability to sit together.