diff --git a/OpenRA.Mods.Common/Traits/Mobile.cs b/OpenRA.Mods.Common/Traits/Mobile.cs
index f3881d6201..620bea4cd2 100644
--- a/OpenRA.Mods.Common/Traits/Mobile.cs
+++ b/OpenRA.Mods.Common/Traits/Mobile.cs
@@ -86,6 +86,9 @@ namespace OpenRA.Mods.Common.Traits
 		// initialized and used by CanEnterCell
 		Locomotor locomotor;
 
+		/// <summary>
+		/// Note: If the target <paramref name="cell"/> has any free subcell, the value of <paramref name="subCell"/> is ignored.
+		/// </summary>
 		public bool CanEnterCell(World world, Actor self, CPos cell, SubCell subCell = SubCell.FullCell, Actor ignoreActor = null, BlockedByActor check = BlockedByActor.All)
 		{
 			// PERF: Avoid repeated trait queries on the hot path