I always laugh when I see someone roll down all their windows when they see me as they try to hide their tinted windows. Almost as funny as those idiots that put their arms over their left shoulder and across their chest to try and cover they are not wearing their seatbelt. They actually attract my attention where I would probably not have even looked at them in the first place.
As for your question, they are not going to tow it just because the windows will not roll up; but they could. They could also tow it for evidence if he has probable cause to believe the windows are tinted and your friend can’t roll them up. Tow it and have a mechanic get the windows up to inspect it.
Vehicle Not Equipped or Unsafe
24002. (a) It is unlawful to operate any vehicle or combination of vehicles which is in an unsafe condition, or which is not safely loaded, and which presents an immediate safety hazard.
Unlawful Operation After Notice by Officer
24004. No person shall operate any vehicle or combination of vehicles after notice by a peace officer, as defined in Section 830.1 or subdivision (a) of Section 830.2 of the Penal Code, that the vehicle is in an unsafe condition or is not equipped as required by this code, except as may be necessary to return the vehicle or combination of vehicles to the residence or place of business of the owner or driver or to a garage, until the vehicle and its equipment have been made to conform with the requirements of this code.
Vehicle and Equipment Inspection
2806. Any regularly employed and salaried police officer or deputy sheriff, or any reserve police officer or reserve deputy sheriff listed in Section 830.6 of the Penal Code, having reasonable cause to believe that any vehicle or combination of vehicles is not equipped as required by this code or is in any unsafe condition as to endanger any person, may require the driver to stop and submit the vehicle or combination of vehicles to an inspection and those tests as may be appropriate to determine the safety to persons and compliance with the code.
Compliance with Peace Officer Orders
2800. (a) It is unlawful to willfully fail or refuse to comply with any lawful order, signal, or direction of any peace officer, as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2 of the Penal Code, when that peace officer is in uniform and is performing duties under any of the provisions of this code, or to refuse to submit to any lawful inspection under this code.
(b) Except as authorized under Section 24004, it is unlawful to fail or refuse to comply with any lawful out-of-service order issued by any peace officer, as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2 of the Penal Code, when that peace officer is in uniform and is performing duties under any provision of this code and the out-of-service order complies with Title 49 of the Code of Federal Regulations.
(c) It is unlawful to fail or refuse to comply with a lawful out-of-service order issued by the United States Secretary of the Department of Transportation.
Now go look up stuff yourself, there is a thread of resources for this.
http://www.bayarearidersforum.com/forums/showthread.php?s=&threadid=165689