Simple answer to the question: Yes, you can get a ticket for exceeding 55 mph while towing. How do I know? I got a ticket for this exact reason.
Several years ago, right after California changed the towing law to include all vehicles towing and the highway signs had not been changed, I was traveling East bound on Interstate 8 several miles West of El Centro, if you know the road. The posted speed limit is 70 mph, two lanes in each direction, and I was traveling in the right lane and set my cruise control on 69 using the GPS.
On the right shoulder, a CHP officer was just sitting there finishing writing a ticket. I saw him, but could not pull over to the left lane to give him space due to another car in that lane.
In my mirrors, I saw him come up behind me and light me up. Long story, made short, I got a speeding ticket. My wife says it's probably because he was upset that I didn't change lanes to go around him.
Side note: my first "driving" ticket in my life, some 45+ of driving. Everyone laughs when I tell them my first ticket was for speeding in the RV.
So, remember that when you visit California, and you are towing anything (car, boat, etc.), you'd better keep it under 55 if you don't want to get a ticket.
