Why did Lyft block my access to scheduled rides?

Recently, there have been increasing complaints that Lyft is blocking driver access to scheduled rides. This is because Lyft has recently tightened the penalties for failing to fulfill a scheduled ride, as follows:

To prevent such situations in the future, we have changed the logic for assigning a ride to a driver. Now, we assign you only those rides whose pickup time is at least 70 minutes away, so you have enough time (10 minutes) to drop the ride with impunity in case you don't like it.