I think that it's simply a matter of getting what you believe you paid for. The implication of an alternative choice may not be clear to the contractor, but it

I think that it's simply a matter of getting what you believe you paid for. The implication of an alternative choice may not be clear to the contractor, but it might be important to the non-technical person (even if they don't specifically know what the technology is). Perhaps the non-technical person had a trusted friend who is a Ruby on Rails expert -- and this person was not available at the time of initial development, but available later to maintain the app?