In defence that’s not a landline issue, that’s a god damn rotary phone. Touchtone phones were invented in 1963. So… people under 60 years old have likely never used them. I’m nearly 40, I’m pretty sure cordless phones were pretty standard in my house.
That being said, yeah even cordless phones, you’d surely know the basestation isn’t where the sound comes from. Though I’d imagine it’s probably just in ease of communicating the joke, as the focus is to make sure the reader isn’t mistaking it to be the girl speaking, as if you put it at the earpiece that’s still roughly where you’d put a speach bubble to represent the girl speaking without a phone.
Least people who do shitty things… don’t tend to make that distinction. It’s often used as a threat to bystanders and even victims. IE I took your lunch money, if you go to the teacher about it, we will beat you up.
If you are talking friends who participate, the implied violence would be unnecessary really. You roll on your friends when doing something against the rules, your friends will never include you in their activities again.