The spell Mage Hand requires an action to move, which implies that it does not automatically move with the caster. The hand also disappears if it moves beyond 30 feet of the caster.
[...] The hand vanishes if it is ever more than 30 feet away from you or if you cast this spell again.
You can use your action to control the hand. [...] You can move the hand up to 30 feet each time you use it.
If the caster is forcefully moved more than 30 feet from the mage hand, then it seems logical that the hand would disappear. However, does that also apply to a caster that is on a moving platform (e.g. on a mount, riding a cart, riding a boat, etc.)?
Maybe on the boat or other large vehicle situation, could it be treated similarly to an Immovable Rod situation. I've seen various responses on how Immovable Rods react on large fast-moving vehicles (e.g. trains), and ultimately up to DM to interpret a relative location.