Why can't walkers change their cancellation policy from "flexible"?

I saw in FAQs that it is not possible to change my cancellation policy from "Flexible". This doesn't seem fair since I rearrange my whole day/week depending on the schedule of each walk. If I'm reading it correctly, the owner could change their mind literally minutes before I start the walk - I wouldn't get paid and they wouldn't get penalized? Is this something that we sitters/walkers will have control over soon? I think it should default to Moderate (like the drop-in visits), but allow users the option to change it to flexible or strict. Can you clarify why it would be different for the scheduled walks?