This is clearly done to play on the insecurities of the less-than-tech-savvy users, who might believe that their machine is now in a worse state than before they ran the app, and need to pay now to get a clean system. Especially with an app that is supposed to clean your system, it's really messed up to run an activity only partially, and then ask for money. While it's OK to provide only limited functionality in a trial version, the appsshould be upfront about what the limitation is. Sneaky about trial limitation and prices Trial version only cleans 500 MB, but it does not disclose that limit before one pushes the button to clean after a scan.
