But Candy Harrington, a top expert in accessible travel, just posted a disturbing blog warning that some agents are overcharging people with disabilities on these sorts of excursions. It seems that agents don't make a commission on the rental of accessible vans and other paraphenalia that people with mobility impairments need. So they either throw these in for free, or add an extra fee to cover their time. Unfortunately, in some cases where agents are adding in a fee, these charges are going through the roof.
Take a look at Harrington's piece for full details and her sage advice on how to make sure you're not being gouged.