With regard to 'tagging along in a race' I agree with screenman. TTs and road races have very strict criteria to adhere to and if the police perceive there to have been breaches of criteria they are likely to pull the event or make it even more difficult to run the next time.
The roads are for public use, we all accept that - that, after all, is why we cyclists get het up about motorists. But we have to respect the other road users as they do us. For me, tagging along in a sportive is no real sin. Anyone could be out on the road at that time. There is no rolling closure and so long as you're not dangerous or taking advantage (nicking food, etc) there's not a lot that can be done. I don't do it myself but that's my choice. But in an actual race it's interfering with a competitive event. A mate of mine was testing one night, had a number on his back, TT bike etc, and some guy started wheel sucking him. He tried to get this guy to get off his wheel pointing out the number, the fact he was actually racing only to be told 'I'm just out for a ride'. Very bad manners in my view, off putting and potentially dangerous.