If you don’t like when customers order without contacting you, I came up with an idea that I think would work great.
Double all of your prices (or some reasonable increase)
Put a notice in red on your gig image: “Send me a message now to save 50%”
it’s also a way to test higher prices, if your orders slow down too much, put a similar banner to attract new customers.
This way, if customers order without contact first, you get paid more.