When launching a multiplayer game, it would be great if the game would do quick verify step by calculating a checksum for each file critical for syncronization such as the airport file, schedule file, and anything else. The game would then compare the checksums on the host against all the clients and flag any files that do not match so the players can fix the inconsistency before starting.
It would be partly a quality of life improvement but could reduce unnecessary bug reports in case people have out of sync files.