Yes, but in the US, it is still legally the airline responsibility to provide assistance even though they contract it out. It means that if something goes wrong, you can then potentially seek compensation from the airline. I did get a $100 voucher from American Airlines when they forgot all about me at an arrival gate in San Diego airport a couple of hours ago. After waiting for a while, i had to call a friend who then called San Diego airport and they sent a security guard to collect me.
In the EU, there is no way to get any sort of compensation or even an apology from the airline. The airport may say sorry but if you want any sort of compensation for all the trouble you go through, you need to go to court. Requiring airline/airport to compensate special assistance passengers makes them far more accountable. Just for the record, I am not one of those people who complains just for the sake of getting a compensation voucher or bonus miles. There is a serious lack of accountability and enforcement in the EU system at present.