[judge2020]

Tethering is mostly a relic of the late 2000's when 3G cellular networks were pretty sketchy; if enough people tethered back then it'd put a huge strain on the network for anyone on that tower. Nowadays the capacity is already planned out with tethering in mind (all tier A plans, eg. direct-from-carrier plans, have some amount of tethering), but it gets pretty murky when you consider people trying to tether on their MVNOs network at peak times/rush hour, really straining the capacity allocated to that MVNO, degrading the service for others.

[Spooky23]

Even with large accounts the carriers still impose limits on tethering. If you’re getting unlimited tethering, it’s probably actually a “pool” of data.”

Even there, there’s some differences as prioritization works differently when you are using pool resources.

[seb1204]

Really?, Which country are you talking about? Here is Australia, I can tether with Aldi Mobile, a reseller of the Telstra mobile network. Works fine in Android and iPhone.

[Spooky23]

The US.

Tethered traffic is usually routed differently. Almost all cellular data traffic is CGNATed or proxied, and different priority is assigned to different types of traffic.

For 95% of users, there’s no problem at all. When people push the limits, they find themselves in a pickle. I’m familiar with an organization with >50k devices across 4 major carriers 4-5 years ago. They probably had <500 people who required some sort of exception, ranging from a different plan to a more appropriate device and plan, to someone doing something crazy. (One guy was running a small field office off of a Samsung tablet)