Deuteronomy 13:1–3 (ESV)
“If a prophet or a dreamer of dreams arises among you and gives you a sign or a wonder, 2 and the sign or wonder that he tells you comes to pass, and if he says, ‘Let us go after other gods,’ which you have not known, ‘and let us serve them,’ 3 you shall not listen to the words of that prophet or that dreamer of dreams. For the Lord your God is testing you, to know whether you love the Lord your God with all your heart and with all your soul.
There is always a danger that we will get off track and into error by looking at what works instead of what is right.
In the reference mentioned above, the truth of a prophecy is one of the tests by which to judge a prophet, but not the only one. If the prophet is encouraging behavior which is clearly condemned by Scripture, that prophet should be stoned whether his prophecy comes true or not.
While we certainly should not begin stoning those who proclaim false prophecies, we should ignore them. We have people who bring all sorts of practical methods into the church to advance her programs and influence. The test is not whether these methods produce results, the test is whether the results are what God desires for his Body.