Our current system of verifying action requires users posting pictures posted to social media and checked by other users to spot anyone trying to scam the system.
A more fun alternative might be a Pokemon GO style system where an digital character (prob different for each activity) appears at the coordinates for each activity, and users get their tokens for finding it with their phone camera’s.
Perhaps the system would require them taking a short video, with the character and them doing the activity together, and the selfie could then be validated before the tokens are released.
The character would need to appear in the video, so our app would have to have a Pokemon GO, Snap Chat style camera function to put the character into the video