They let her get away with that $2MM in order to skip auditing somebody else.
When she spent long enough they canceled her card and she had to apply for a new one.
Can't leave the country if she can't cash out from that card.
The IRS will pay $25K REWARD MONEY to your own family to rat you out for $2MM, that why she tried to lay low and get a used van like a regular tax refund.
What ever she spent was pennies interest compared to the annual budget for investigations.