You are of course, correct ... unless your computers are behind a firewall controlled by a totally anal network communications person who knows that his/her job is forfeit if a virus hits the LAN. In this scenario, alternative methods are viable.
Because of the proliferation of computer virus programs, it is becoming difficult to send/recive anything but a plain-text e-mail. Any communication with an attachment is quarantined, sometimes without regard to the type or content. At the rate that e-mail lockdowns are happening, I forsee the return to snail-mail as the preferred method of casual information exchange.
... makes one wonder if the USPS might be in the virus business ... /sarc
If youtube is blocked at your place of work, then that means the issue of saving videos from that site is irrelevant. You can’t even see them in the first place! Why did you even click on the topic?