If you really like the person, think they have huge potential and are concerned over some of their business decision, I suggest you try being his/her friend and support them, by telling them the truth --- it is not like you are telling them something personal (aesthetics or blah blah), you are simply trying to help them with their future. If the person is truly making a pile of bad business decision, and is your friend, they will appreciate your time, effort and the amount of cash you'll save them.
Ignoring, or avoiding the issue is not something a friend would do and may create some tension between the two of you (for holding back).

That's my one-cent - I used the other to buy a Mojo (banana flavoured, BTW)!