Earlier today a supposed Samsung Experience Shop rep posted on Reddit that it was possible to get the Galaxy S5 updated to Android 5.0 Lollipop through these shops which are located inside Best Buy stores. The rep claimed that at start of business today binary code for Android 5.0 was downloaded in the tool that Samsung Consultants use to flash firmware. Those who wanted to update and jump their carrier's timeframe only needed to take their unrooted units to the SEC and get updated to Lollipop for no charge at all.
So far only Verizon and Sprint are the two major US-based carriers that have released Lollipop for the Galaxy S5. Users on AT&T and T-Mobile are still waiting.
The supposed rep said that units on all US carriers, even those on MetroPCS and Boost, would be compatible except T-Mobile units and that's because Best Buy doesn't have a relationship with the carrier other than for sale for prepaid phones. The Galaxy S5 units just need to be on the latest official firmware for the procedure to work.
In theory this seems like the best option for users to get Lollipop on the Galaxy S5. However on the same reddit thread there are countless comments from people who said that they haven't had any luck with this. They took their units to SES at Best Buy, some even tried out multiple locations, but they were told that the update was not possible.
Furthermore there haven't been any independent reports of this method working for anyone. It looks like the only way users in the US can get Lollipop is to wait for their carriers to hurry up and release the update.
So before you venture out for a trip to Best Buy just for the update it would be better to call ahead and confirm, and keep in mind that Samsung Experience Shops are only located at select Best Buy locations.