diff --git a/code/game/ai_dmq3.c b/code/game/ai_dmq3.c
index 7248645c..75749229 100644
--- a/code/game/ai_dmq3.c
+++ b/code/game/ai_dmq3.c
@@ -2876,6 +2876,7 @@ float BotEntityVisible(int viewer, vec3_t eye, vec3_t viewangles, float fov, int
 		BotAI_Trace(&trace, start, NULL, NULL, end, passent, contents_mask);
 		//if water was hit
 		waterfactor = 1.0;
+		//note: trace.contents is always 0, see BotAI_Trace
 		if (trace.contents & (CONTENTS_LAVA|CONTENTS_SLIME|CONTENTS_WATER)) {
 			//if the water surface is translucent
 			if (1) {