170
Shit like this is why I am always on my guard against offers of "free" anything from corpos. Always.
(i.imgur.com)
Sometimes they even get rubes to pay for the privilege of being exploited and sold off in marketable pieces, such as 23andMe. 
Some courts see arbitration provisions as an usurpation of the court's jurisdiction and will refuse to enforce them against consumers if the corporation is seem to be hiding them in general terms and conditions.
In other words, McDs would bury the shit out of that clause if it's lawyers felt like if could.