Unlimited PTO to me would only be interesting to me if you had a policy stating the minimum number of days/hours you must take a year. Reminders are nice and all but (written) policy is better.
Thanks for your input. Somehow my employees manage to take lots of time on their own as ultimately they have agency, not me. There is no cultural blocker to them taking time (that I'm aware of).
More correctly: I state that I do not have a time-off policy. This is mainly to prevent administrative overhead - something that a minimum number of days would require. I know this won't scale, so I imagine we'll have a "formalized" vacation process long term, but I'm not there yet and don't plan on being there for at least 2-3 more employees.
Illustrating the "no cultural block" point: I had an employee tell me on a Wednesday that he needed the week off the next week to unwind for mental health reasons. I moved a few things around with customers and he happily enjoyed the week. That is signal enough to me that my employees feel fine asking for time off.
None of the employees I have in the states they work in require me to pay out accrued vacation/sick time by law, so your point is moot because I wouldn't offer such a benefit anyways. That said, your cynicism is noted.