observations are really "important caveats"

tsa/howto/conference.mdwn

@@ -117,7 +117,7 @@ Cost estimate summary:
 | Jitsi           | 74 hours  | €54 + 10 hours |                                     |
 | Big Blue Button | 156 hours | €54 + 8 hours  |                                     |
 
-Some observations:
+Important caveats:
 
  1. **Mumble is harder to use** and has proven to absolutely **require
     a headset** to function reliably