A report about hands-free cell phones that aired on Channel 4 last week shows why this principle is absolutely vital. The package found correspondent Shaun Boyd testing out different devices, using as a hook legislation that may make driving while using handheld cell phones a ticketable offense. Her commentary was supplemented by remarks from Jeremy Linehan, a spokesman for Car Toys -- and after the piece had run its course, anchor Karen Leigh popped up to announce that the company is offering CBS4 viewers a 15-percent discount on hands-free phones for mentioning the story. This appalling and embarrassing tie-in offers short-term gains when it comes to pleasing advertisers. But it makes Boyd and Leigh look like shills who are in the pocket of Channel 4's money-siders -- and that hurts the station, and their reputations, in the long run.