Client access license. For Microsoft Windows they come in per-seat and per-machine. To OPs point, they were talking about RDP. When you are licensing per-machine then (windows server) you are limited to one desktop user and two remote users (for windows desktop it’s one user at a time). When it is per-seat then you can have as many concurrent connections as you have licensed for. Per-seat is enforced by Microsoft Licensing Server

I was mainly referring to personal pc uses, not corp/server users.

It's still technically breaking the license to override TERMSERV.dll's protections on home/professional PCs not allowing somebody to be logged in while somebody else is already logged in.

ie, a home or professional licensed pc can not support 1 user on remote desktop, and 1 user sitting down in front of it at the same time, you have to pay for a server license to get that functionality. This technical limitation is considered a DRM measure and also protected by the DMCA anti-circumvention provision.

if you don't mind breaking the law, I was pointing out how you could use abuse 127.0.0.2 to connect remote desktop to localhost in other to do seperate user accounts for seperate tasks, (such as putting your job hunting activities in a seperate account so you don't get distracted by discord/chrome desktop notifications and reddit in your new tab page)