Yeah, my friend ran a small design shop and did the same thing. He had this star designer who kept pulling all-nighters for client pitches. One Tuesday, she just didn't show up. Sent an email saying she was done, didn't even get her stuff. He found out later she took a job paying less just to get her nights and weekends back. He had to basically start over, hiring two juniors to replace her, and now he's super strict about weekend emails.