John List and Uri Gneezy conducted a series of experiments to evaluate discrimination against disabled people seeking car repairs:
[W]e recruited several men between the ages of twenty-nine and forty-five to act as our secret agents. Half these men used wheelchairs and drove specially equipped vehicles. The other half were non-disabled, but in all cases the individuals hopped into a specially equipped vehicle for the disabled with a fresh ding on the side and headed to Chicago-area repair shops.
When our secret agents got to an auto repair shop they simply asked for a price quote to fix their car. What we found initially was shocking. The disabled were given quotes 30 percent higher than the quotes given to non-disabled for the exact same repair!
Curious about the extent to which car repairman were motivated by hatred or just profit motive, though, we did one run of the experiment where both types of our secret agents got a quote and told the repairman that they were, “getting three price quotes today.” What did this extra sentence do? Well the figure shows that for the able-bodied subjects, their price quotes didn’t change at all, but for the disabled they plummeted. Furthermore, the difference in prices for the disabled and abled disappeared.