[petropolis]

I don't want to set the pin because I have other clients that assume it is empty. Can this get fixed?

[lasers]

You can set it to all zeros.

[janbar]

I don't want to set the pin because I have other clients that assume it is empty. Can this get fixed?

The PIN code is mandatory to work with the API of MythTV backend (Please look at the MythTV documentation). If your others clients don't need a PIN code, then they don't use the REST API, so setting the PIN code shouldn't disturb them.