With the Slingbox 500 50 Hz/PAL is not a supported content. With the 500 meant to be sold in the US and Canada only the Slingbox is equipped to take sources that are in those regions. Being that you are using the Slingbox 500 in an non-supported location I am glad it is working for you. If you see any change in this there is little that can be done. Being that the unit is not meant to stream that content we cannot guarantee that it will continue to stream and therefore if a future update stops your Streaming of this content we are sorry, There are many reports of people setting up these units in other countries and them working, This is great but not totally supported and we cannot make any guarantees for all of you who are streaming outside of the US and Canada.
Thank you for choosing Sling Media
Sling Moderation Team
Interesting that you only recently put up the article saying the European sources aren't supported...
Good luck dealing with the fallout if you break this in future, as when people imported these boxes there was no such indication that it didn't work with European sources, regardless of whether it was officially released in Europe or not...