Like stated above they can terminate you as soon as you give notice and not pay you for those 2 weeks.(I have seen this numerous times in the aftermarket industry.You decide your leaving and they want you gone before you can steal product,ideas,etc...)
If it were me and she had personal/vacation days I would use them before she quits.They only have to pay vacation so those days will go to waste.
Maybe Linda can go into greater detail but a couple years back I had a job that was going to end up cutting back on commisions so I took several days off before I left and they couldn't do anything about it because no Dr. Notes are required if you are gone 2 days or less.