Can hidden units be played at Rockfall Path, and how do they interact with it?

Ruling: You cannot play hidden units at Rockfall Path. While you can hide a unit card there, you cannot reveal and play it because you need a valid location to play a unit and cannot make illegal choices.

Sequence:

• You can hide a unit card at Rockfall Path
• When attempting to reveal it, you would need to choose a valid location to play the unit
• Since no valid location exists at Rockfall Path, you cannot reveal and play the card
• The card remains in hidden state

Nuances:

• Hiding a unit at Rockfall Path can be used as a bluff to make opponents think you have a spell
• This is a tempo loss but provides a strategic deception option
• Choosing a location to play a unit is not targeting, but you still need a valid location