There is a possibility that the VPN could be used to hide IP Addresses accessing illegal sources on the inter-web, or hide traces of more cyber-attack preparations.
Changes that may occur during the useful lifetime:
Although the majority to the project will be in the hands of the user, there could definitely be some updates or additions to the VPN that could monitor usage, average download/upload speed, and even have a "sleep" timer to configure the Pi to activate based when entering hours with higher usage.
Disposal:
Although disposal of the product would most likely be unnecessary, Raspberry Pi disposal directions would be attached in the users' original packaging. In addition, steps for removing the VPN and corresponding files would be given to the user as well.