They could very well store your card information even if they don't fraudulently charge you outright. They could even legitimize this action under the guise of server-side credit card number validation.
That's different than charging though. A lot different. There's no real way of knowing what goes on under the hood when putting your info into a web/app form like this, but if I was charged for something without pressing the actual buy button then "Houston, we have a problem".
True, that would certainly be not as worse and downright illegal as charging. It still seems very slimy, though -- why are you storing my CC details when I never actually made a purchase on your site?