The devices of our free VPN customers are used to create a secure peer-to-peer network that our commercial clients can use to securely route their traffic via various global endpoints. As a free client, you will likely not notice any impact on your resources as that happens. The data transferred in the background will be metered by your mobile operator according to your data plan.
https://bigma.org/faq.html
I mean at least they’re saying it. Will the average person read this or understand it? Nah