Wow Coggie old boy…don’t get your rolling pin dislodged…I get it, I really do. I stereotype all the time. For example, I know that all chimps are incapable of detecting sarcasm.
Seriously though, sometimes it is more a thing of pattern recognition. In those situations as you described above, quick evaluation is demanded and time indeed might enter into the equation. Stereotyping is, in general, an oversimplified generalized definition or identification or even belief which is held, and often employed as an intellectually lazy or dishonest response. I find it similar to or even commensurate with deeply held prejudices when used as such. Sometimes it is just a recognition of a pattern. It is good advice to “be careful”…