OP here. I'll refund the last month's payment regardless when canceling, no matter how long you've been a customer.
The goal isn't to trick people into paying. The goal is to make it feasible for one person (me) to support a product by attracting those who have a business case for using it.
It occurs to me I'd have a much less negative reaction to what you're doing if instead of calling it a "free trial", you called it "first month is free" (like landlord rental deals), or "will refund your money in the first month if you aren't satisifed," or something like that.
Now, these end up being essentially the same thing, but if you marketted it like that would it hurt conversions? I don't know. But if it _would_ then it would definitely make me suspect that many of your conversions are accidental, and accidental conversions are the shady part, right?
The goal isn't to trick people into paying. The goal is to make it feasible for one person (me) to support a product by attracting those who have a business case for using it.