One can get a 2" trailer ball that is good to 10K lbs. 2 5/16 typically can be found upwards of 15-25K lbs. I've even seen some 2 5/16 as low as 5K rated! All depends upon the shank size frankly!
Many trucks with motors of the Jettas specs are rated to tow upwards of 5-6K lbs. Other than the frame strength, I personally do not see the issue with this jetta towing the trailer. For all you screaming bloody murder about it......you may not like it, "IT IS A LEGAL SETUP!!!" Now from a manufacture warranty stand point......that is a whole nuther issue!
Marty