All requests go through the business router which can log what machine asked for what.
It does not matter how. It's their network and the business can track all accesses. If employees don't get the message soon, they may not be there long.
At my workplace we recently received a warning that we need to get off the internet during work hours. Half of the shop uses laptops, and the other half desk tops. Originally the desktops were monitored by software that prevented access to non work related sites. Those that worked on desktops were told that the websites they searched for could also be tracked. Obviously due to the software.