If you use your Clipper card to transfer from a San Francisco BART station to a Muni vehicle or metro, there's a change in policy regarding the transfer rule.
The old rule:
When exiting BART from any station between Embarcadero and Balboa Park, you have one hour to transfer to Muni. When tagging the same card you exited with BART and use it on Muni, you get a 25 cent discount on your Muni ride. When you are ready to take your next ride on Muni (after the Muni 90 minute transfer expires and its less than 24 hours from the time you exited BART), your next Muni fare transaction is 25 cents off. This is the exact policy just like when BART stations issued paper discount transfers which gave the same benefit.
The new rule:
When exiting BART from any station between Embarcadero and Balboa Park, you have one hour to transfer to Muni. When tagging the same card you exited with BART and use it on Muni, you get a 50 cent discount. There is no discount for a second ride.
Note: This policy is not valid if you have a Muni monthly pass. It must pay in Clipper e-cash funds. As always, if you have a Muni monthly pass on your card, Clipper always seeks the best deal, instead of yanking $1.50 out of your pool of funds.
Also, this policy is not in use at the Daly City BART station. Passengers still get a free ride on any Muni line that serves Daly City BART.
How did I notice the change?
When I go to baseball games at AT&T Park, I have to take BART and Muni metro to and from the park. I noticed when I tagged my card on the Clipper card reader to get back after the game, I had to pay full fare. When I got home, I reviewed my Clipper card records online and found out that there was that change in transfer policy.
Akit's Opinions:
It's a simple change that makes it more simplified for Clipper card users. Instead of wondering if the return ride 25 cent discount works, you just get the full 50 cents off in the first Muni ride away from BART. I like it.
Reference to policy: https://www.clippercard.com/ClipperWeb/muni/fares.do