✗- A Mare with a foal that's only been played for 2 weeks must keep the foal with her if she is stolen, as it would still be nursing.
A foal played less than 2 weeks is not safe, it is just assumed to be by its mothers side so is she gets stolen it'd go with her, also 2 weeks old foal would be like, fail at resisting. If a 2 week old foal is targeted however, it's assumed it ran off from it's mothers side, and likely would need milk provided by its captors.
Just to clear that up~
Magic or force permitted any time, aside from death.