Is that legal?

Probably not..
People asked me this kind of questions in many circumstances..mostly when I started doing something creative. I don't know why people are concerned so much about breaking rules..
well..I did mean to say that one should violate red light or throwing trash in the river or stab someone he doesn't like. It is kinda common sense that such behaviors will lead to undesirable consequences.
Yet, I would say that many rules are simply artifacts of bureaucracy and don't really benefit anyone.
In fact, if you're serious enough to look though all possible rules you might have accidentally broken over the past days or weeks, you probably find some.
My sense is, if you don't directly inflict a pain to someone, the chance that the law enforcers will go after you is pretty low. From my experience, I bureaucracy is slow.. slow to respond when you ask for a permission.. and slow to punish to you when you did break rules.
So, the bottom line is, if you need to break some rule to get your work done (I'm sure your work is important for mankind!), don't worry too much.