http://www.netflix.com/ - front page free trial!
Type in your email and a password. While you'll see the monthly price clearly listed, you'll also see Free Trial Offer Details in really tiny text on the left. If you click on it, it tells you how you will be charged unless you cancel. Those sly bastards
This is a similar model to the video professor.
On the video professor page it does tell you, after you click to get the free trial, that you can avoid a full charge by canceling. It also says this on their home page. In fact, it's on the right side of the page on every page of the order process up until the credit card entry (which is where I stopped).
Any decently intelligent individual would know there will be some charge at the end of the trial. It is quite clearly stated as a trial. And because it is a trial, it doesn't matter what the full price is, just as long as you know you can cancel. Which you can, by the way.
So sure, it's very likely that a legitimate business would not be so tricky. So the odds are, maybe they do have bad intentions.
I don't have enough evidence, and Arrington didn't seem to have tried to procure much either.
So there is doubt.