Not really. Popcorntime doesn't provide copyrighted material, it just helps access and consume it, same as your laptop, TV, Chromecast or cellphone. Besides, the technology behind Popcorn could be used to access open content, therefore, the Berne Convention doesn't explicitly apply here.
I wonder if it'd be difficult to add an index from vodo.net to Popcorn Time. If they also added a link to the pay/donate API, that might actually give some of the Vodo.net-releases some much needed money (given the market share Popcorn Time apparently has).