It depends on the restaurant and the table size needed for your party and what is going on. We once had a larger party at Cape May Buffet and had a seating for, I think, 6 PM. We had 10 people and when I made the seating, I was told there were no tables that seated 10 all together. That was fine, I just asked for tables next to each other as I was told the largest table they had was for six. So, I got a six top and a four top. Once we all arrived at the restaurant, we were told our two tables were next to each other and that the parties who were occupying the tables were finishing up so it wouldn't be long (the parties were not with each other). After fifteen minutes, we were told that the one party had left but the other one was still there "enjoying themselves" so they could seat four people but the other six would have to wait. We decided to just wait until the other party left. Once that happened, we had tables next to each other.
Another time, I had a party of twelve and we were at 50s Prime Time. They put us at three tables of four next to each other but when I checked in, was asked if I wanted the tables pushed together or left side by side. I joked and said "for a few of these people, put them in another room but I guess we'll have them pushed together".