Yeah those cases are sad. I tend to just say my prices really high, and if they persist in wanting me to come out I suddenly don’t have availability because of the “big government project” I’ve been hired to do. Even if they were worth the trouble of all the follow-up “someone broke in, you have to fix my locks” calls that inevitably come, I couldn’t in good conscience take their money.
Last time it happened a lady wanted me to install Schlage Primus deadbolts on her house because her neighbor was “breaking in and moving things to mess with me”. I gave her a quote that was 5x higher than it should have been. I kid you not, she said, “Okay, but I’ll have to wait a couple of weeks to get the money. My husband said I couldn’t change the locks anymore and that this is all in my head.” Poor lady. I saved her number so I wouldn’t forget if she called again, but I never heard from her. Hopefully she got the help she needed, but probably she got divorced and is living on the streets.