That's not SOP at Google except in very limited circumstances. When I resigned, I told my manager and we negotiated an exit date 2 weeks after. I volunteered to give up my laptop early etc and not come into the office, but they really wanted me to finish up. People who steal or leak, however, could be terminated immediately and walked out by security. I guess also if you worked on a competitive product and changed to a competitor, they'd walk you out, too.

I’m not arguing that she did or didn’t resign, just that she didn’t say “or my last date is the 10th” or anything else that clear.