Regardless of what "the book" may say, I am surprised that the question even comes up. Considering to "take on" a ship or tug is like looking at the bore of a 12 gauge shotgun held by the skipper who is politely asking you not to get in his way. "You can think about it, but don't do it".
I disagree. Colregs say the stand on vessel must stand on. The reason is the tug guy will be looking at his options before you've even worked out hes a tug towing. He, and only he knows how his tug and tow handle.
If you are not keeping a course he cant work out what to do. Also remember that when he is pulling, the direction of the bow of the tug may have little to do with the direction the tug, line and barge are actually going. Only the tug captain knows.
Best is having AIS so you can see him and he can see you. Then if you hold your course he can make his judgement and get on the VHF to you. Anytime a tug, or ship, asks me to do something I am only too willing to comply. Doesnt worry me if i have to stop, or turn, or whatever, but its much better, as the stand on vessel to keep a good course till asked to vary, imho.
Re: lights on barges... The world over it seems barges lights must be the lowest priority in shipping.
The best one was in Indonesia at night and Nicolle dragged me out of be to work out what the hell the christmas tree of lights was all about. Giving a thought that it could be Santas sleigh or a tug, I told Nicolle to look a LONG way astern to see if she could see a barge with the binoculars. "Nope, no barge, but theres a funny purple haze"
That purple haze was a reflection of the watchmans TV set in the watchmans shed! And we were much closer than I thought. Lolol
The USA may have been better for tow lights than Indonesia, but not much better, and the Caribbean is taking the fight up too