update the readme for URIBeacon

BLE_URIBeacon/readme.md

@@ -48,4 +48,8 @@ beacon detectable by BLE scanners (e.g. a smartphone).
 
 This may or may not be useful, but you'll find [links](https://github.com/google/uribeacon/tree/uribeacon-final#contents) on Google's project page to client apps to test URIBeacon. Here's a link that should get you an [Android App](https://github.com/google/uribeacon/releases/tag/v1.2); please browse to `uribeacon-sample-release.apk`. But you should begin with the links to android apps mentioned above.
 
-**Please note that the URIBeacon spec. requires the URIBeacon app to remain in config mode for the first 60 seconds before switching to being a beacon.**
+**Please note that the URIBeacon spec requires the URIBeacon app to remain in
+config mode for the first 60 seconds before switching to being a beacon. So if
+you're using a physical-web app, you'll only see the beacon after this period;
+if you're using one of the generic apps for BLE scanning, you should see a
+configurable beacon being advertised for the first 60 seconds.**