I feel like the dodgy part isn’t the forking. Any open source project can be forked at any time by anyone. The dodgy part is them automatically switching existing users to their fork.
To use your McDonald’s analogy, it’s like specifically ordering a Coke and McD’s secretly switching it to a McCoke without you noticing.
To use your McDonald’s analogy, it’s like specifically ordering a Coke and McD’s secretly switching it to a McCoke without you noticing.