FORD's 36k COMPLIMENTARY ROADSIDE ASSISTANCE:
If you have a flat tire, they will come out to change your tire for you for NO-CHARGE ... however your car MUST HAVE A SPARE TIRE !! Does not sound like hauling your car away on a flat bed because it has a flat and no spare is part of the FREE service.
Here is the text from the 2012 Mustang Owner's manual page 229
...
Roadside assistance will cover:
-a flat tire change with a good spare (except vehicles that have been supplied with a tire inflation kit)
...
-towing - Ford and Lincoln eligible vehicles towed to an authorized dealer within 35 miles (56 km) of the disablement location or to the nearest authorized dealer. If a member requests to be towed to an authorized dealer more than 35 miles (56 km) from the disablement location, the member shall be responsible for any mileage costs in excess of 35 miles (56 km)
That sure sounds to me like you can request to be towed if you have a flat tire (I'd say it counts as disablement). Especially if you don't have a good spare tire whether you have a tire 'repair' kit or not.
Also, I guess depending on the definition of "supplied" (either came with the car or aftermarket) then the flat tire change may not be covered on a V6 model or GT with
Brembo's that didn't come with a spare even if you've bought one aftermarket. I doubt the tow truck operator would car but it's something to keep in mind.
Also on page 239 it says:
Have a flat serviced by an authorized dealer in order to prevent damage to the TPMS sensors
and
WARNING: The use of tire sealants may damage your tire pressure monitoring system (TPMS) and should not be used. However, if you must use a sealant, the TPMS sensor and valve stem on the wheel must be replaced by an authorized Ford dealer.
Seems like they would rather have you tow your car to a dealer than use the tire repair kit which should only be used as a last resort. Neither the owner or the tow truck operator is qualified to service a flat beyond just taking it off and putting on a spare.
EDIT:
PS. The roadside assistance is 5 years 60,000 miles (not 36,000 miles)
http://www.motorcraftservice.com/pubs/content/~WOBMUS/~MUS~LEN/40/11frdra1e.pdf