For a very long time I've had a set of "nocut" layouts which I believe were originally created by
@Captain Condescending (the set includes most if not all of the stock tracks). These layouts have modified surfaces.ini files (to make cutting more readily noticed/penalised by the sim). I have never experienced a checksum error despite racing on many public and private servers, some of which must surely have had the files available to perform the checksums.
On this basis, despite not having deliberately tested with a server which I am
100% certain to have the content for checksumming (or at least not that I can remember!
), I'm pretty confident that the checksumming isn't affected by a fresh layout with a modified surfaces.ini.