Am I the asshole?

So I clean 3 houses weekly on top of my work from home night job…My Monday client has a tendency to cancel on me last minute taking away from that day of income Due to the fact they keep canceling last minute (I’m talking 5-10 minutes before I’m supposed to start cleaning) I have implemented a new policy that last minute cancellations will result in a 50% service fee

I told them to avoid a cancellation fee then I need at least 24 hour notice…They are of course mad about it but i wouldn’t have put this policy in place if they were respectful of my time and gave more notice but no they do this a lot