Thank you @lissajous for providing the needed details. @jooize sent me the same details in a PM and I provided some information he sent them. Hopefully this will solve their problem. Here's my answer for the record:
Even if they did not mint they certainly received split outputs from their users. Disabling their own splitting will reduce transaction size by about half if they don't already, and will also prevent further splitting while they mint.
Disabling minting would be a good to reduce CPU usage and to prevent shares from being locked. But it's not possible right now without altering the source code. I added an option to disable minting already but it hasn't been released.