[ced]

What prevents you from walking away without paying? (that's a genuine question, not a flippant remark)

[Estragon]

Nothing. I did it once, in a particularly abusive situation in Boston.

[tptacek]

I'm guessing you're male, young, a US resident, and not physically disabled. Tweak any of those variables, conduct 10 trials with an otherwise randomized population, and see how the results compare to your experience.

[tptacek]

Physical intimidation.