Met with a customer a few weeks ago regarding a patio install. Explained a lot about what makes a paver 'interlocking'. I encouraged them to get other quotes but cautioned them to compare my specs with other contractors specs to get a fair comparison. Get a call back from her today and she says she went to the icpi website and looked up some other certified installers. One came out last week and met with them. The homeowner asked what he would use for is bedding material, his reply was stonedust. He begins to explain to her how its fine to use because it drains better than sand!! She then starts asking me "I thought you said concrete sand was to be used under the pavers? How come this guy is certified doing the wrong thing?" WHAT!!!! Now I'm stuck trying to defend ICPI. My response was you need to find a contractor that will meet or exceed ICPI specs and just because contractors are certified doesn't mean they are going to follow the specs. What would you have done/said?