It all depends on the people in the relationship. I like to be in committed relationships, but I also like to point out girls (and sometimes guys) that are cute.
Because well, while I'm in that relationship, it's not like others will stop being cute or whatnot. I know myself, and I can flirt without the intention of cheating.

Again, it depends on the people. General rule? I would just err on the cautious side.
Most people are insecure and would automatically say that it will lead to more.