Earning the time-locked mining rewards is opt-in. If someone wants the time-locked mining rewards that the users/holders are offering them in return for mining services, then they can mine and they’ll receive those rewards. If don’t want that, then they can choose not to enter into that deal. That’s voluntary, consensual cooperation. Note that in the the next Network Upgrade (NU2 — Blossom, activating in the fall of this year), the new time-locked-rewards feature will only apply to the newly-introduced alg-B mining, not to the current miners.