SubFloorHide requires entities to be anchored by default.

Content.Shared/SubFloor/SubFloorHideComponent.cs

@@ -1,4 +1,6 @@
 using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
 
 namespace Content.Shared.SubFloor
 {
@@ -13,5 +15,12 @@ namespace Content.Shared.SubFloor
     {
         /// <inheritdoc />
         public override string Name => "SubFloorHide";
+
+        /// <summary>
+        ///     This entity needs to be anchored to be hid in the subfloor.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("requireAnchored")]
+        public bool RequireAnchored { get; set; } = true;
     }
 }

Content.Shared/SubFloor/SubFloorHideSystem.cs

@@ -68,8 +68,7 @@ namespace Content.Shared.SubFloor
             var transform = ComponentManager.GetComponent<ITransformComponent>(uid);
 
             // We do this directly instead of calling UpdateEntity.
-            if(_mapManager.TryGetGrid(transform.GridID, out var grid))
+            UpdateEntity(uid);
-                UpdateTile(grid, grid.TileIndicesFor(transform.Coordinates));
         }
 
         private void MapManagerOnTileChanged(object? sender, TileChangedEventArgs e)
@@ -113,6 +112,7 @@ namespace Content.Shared.SubFloor
         private void UpdateEntity(EntityUid uid)
         {
             var transform = ComponentManager.GetComponent<ITransformComponent>(uid);
+
             if (!_mapManager.TryGetGrid(transform.GridID, out var grid))
             {
                 // Not being on a grid counts as no subfloor, unhide this.
@@ -134,6 +134,18 @@ namespace Content.Shared.SubFloor
             if (subFloorHideEvent.Handled)
                 return;
 
+            // This might look weird, but basically we only need to query the SubFloorHide and Transform components
+            // if we are gonna hide the entity and we require it to be anchored to be hidden. Because getting components
+            // is "expensive", we have a slow path where we query them, and a fast path where we don't.
+            if (!subFloor
+                && ComponentManager.TryGetComponent(uid, out SubFloorHideComponent? subFloorHideComponent) &&
+                subFloorHideComponent.RequireAnchored
+                && ComponentManager.TryGetComponent(uid, out ITransformComponent? transformComponent))
+            {
+                // If we require the entity to be anchored but it's not, this will set subfloor to true, unhiding it.
+                subFloor = !transformComponent.Anchored;
+            }
+
             // Show sprite
             if (ComponentManager.TryGetComponent(uid, out SharedSpriteComponent? spriteComponent))
             {

SpaceStation14.sln.DotSettings

@@ -264,6 +264,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Spirate/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Strippable/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=stunnable/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=subfloor/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Superconduct/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=superconduction/@EntryIndexedValue">True</s:Boolean>
     <s:Boolean x:Key="/Default/UserDictionary/Words/=swsl/@EntryIndexedValue">True</s:Boolean>
@@ -284,6 +285,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unequip/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unexcite/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Unequip/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=unhiding/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unlockable/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unobtanium/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Unoccluded/@EntryIndexedValue">True</s:Boolean>