Yes. It violates the DMCA (Digital Millennium Copyright Act) and software copyright laws. While RE:Vision rarely sues individuals, they do work with Adobe and Apple to remotely disable cracked plugins via security updates.
: You can download a free trial version to test the features. Note that the demo version will render a red "X" watermark over your footage until a valid key is entered. Activation Key Twixtor
If you are a student or teacher with a valid .edu email, RE:Vision offers up to 50% off. You can get a legal activation key for approximately $165. This is the best value for students learning speed ramping. Activation Key Twixtor