I dont care who comes up to me during meals. I am getting paid and the meal is second to me. Also avoid the "drunk time" right after the bars close. Always can find someone who will let their mouth volunteer themselves into a ride to the station. Once most of the population is tucked in, then we will grab a meal, by self or group of two or more tables. Facing door, window, salad bar, you name it. But trust me when i say we are more aware or you then you know. We probably mention everyone who walks in. Never know when Johnny ****bag decides to get a late bite. But we are ready to say hi to him. Are we more aware then you... cant answer that because a general statement is usually wrong. But we do train in the Wild Bill Hiccock door theory.
Now a subtle or sneak attack can give the aggressor the upper hand for the first moments of any confrontation...but who prevails will be determined by much more.