The “Moved” property - I guess depending on the module/application - really means “activated” ie a piece is “marked moved” and so, Moved can be true even if the piece has not physically moved.
Would it be useful to have another Property - let’s say HasTrail - which becomes true if a piece acquires a trail? The Property would be set false when the trail is cleared (actually cleared, not just hidden).
How would you achieve something akin to this ability within the current Vassal (v3.4. ? I can’t think of a way that doesn’t involve the high over-head of setting a dynamic property or two in every piece on the board to store the location of the piece at the start of every turn.