From Freakanomics(which I highly recommend):
But before we get ahead of ourselves, here’s how the experiment ran: First, we 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!
As almost always with freakanomics, the answer is not quite as simple as strightforward discrimination:
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.
The thing is not that any of these salespeople thought ‘People in wheelchairs deserve to pay more’ – it’s that they thought ‘people in wheelchairs are less likely to have the time and energy to get lots of quotes, so I can gorge them a little bit here…’
From a scientific perspective, there are things you can pick on here, but I think the point is worth looking at generally – that if you are in a wheelchair, people assume you’ll be satisfied with less… and I’m not really a fan of that view…