Earlier quoted context omitted.
> She offered to resign on a particular schedule It is not out of the ordinary at all for companies to walk people out on the day of resignation. The company is not required or even expected to abide by whatever schedule is presented to them.
If the employee says "I'm giving you 1 month formal notice of resignation", and the company responds with "effective immediately you are terminated without pay or benefits", at that point it's not a resignation any more, it's a termination. In most countries (which are not "at will"), I believe if the employee had not breached their contract they could claim wrongful termination in this scenario and likely be awarded…
You can't just say "i'm giving you 1 month of formal notice of resignation" and expect the company to be bound to that month... otherwise, to take it to extremes, what's stopping you from giving them a 20years formal notice of resignation?