The Gray Area of Tax Law

A lot of times a lawyer will give advice and it pushes the envelope and the client says let's go for it. Is that kind of advice criminal? I'm hesitant to say that it's criminal but it's certainly moving into that gray area where there could be some problems. Does a lawyer have to report a client if he or she suspects the client is doing something illegal like inflating assets? It varies largely based on the situation and the state that you're in because you're talking about largely state legal ethics rules which vary from state to state.