As long as the client do not testify, then it is perfectly legally OK. If teh client testify and
his lawyer know it is lie and allow it, then
it is not legal (many still do it anyway).

So it is a tactics a lawyer ask his client
do not even tell anything to laywer so that whhen
teh client testify and tell lies, the lawyer
is legally OK because he does not know
whether his own client is telling truth
or not