As a precursor and requirement for implementing companies, the career state should be synced between the server and all clients. This includes licenses, garages, and money. All of which should be fully server-authoritative. The client should never give itself (or take away) a license, garage, or money. If a client does do any of those, it shouldn't matter as any actions requiring them will be requested by the client, processed by the server, with the result being sent back to the client.
As a precursor and requirement for implementing companies, the career state should be synced between the server and all clients. This includes licenses, garages, and money. All of which should be fully server-authoritative. The client should never give itself (or take away) a license, garage, or money. If a client does do any of those, it shouldn't matter as any actions requiring them will be requested by the client, processed by the server, with the result being sent back to the client.