She is not being "imprisoned", she will be detained at IDC pending deportation which is completely normal for overstayers arrested before leaving at the airport, especially those who have been banned from the country previously.
Yes, sure is, the difference is that she was not at the airport on her way out where the conditions you reference would apply. She was arrested and her overstay discovered, that means detention and deportation.
Nonsense, not everyone is put in jail and that is not the practice here. Her case will be solved easily, there is no difficulty there. She will be fined for her repeat overstay and deported when she comes up with money for the ticket. You think she should be free to make her own way to the airport at her leisure? What do they do with repeat overstayers in your country?
"Karon Police set up a checkpoint outside the Holiday Inn Resort Phuket to monitor both Thai and foreign motorists violating traffic laws".
The articles here are aimed at a foreign audience hence the report of the foreign offenders which doesn't mean that Thais weren't also targeted.