If everyone in the street knows you are under pressure, watch what happens - even getting $0.9999 back on the $ of your "deposit" would probably have people being upset. And 7 days to get your money is probably longer that what people expect.
You wouldn’t need to wait 7 days. The price of a short-term treasuries is purely based off of the current interest rates. Given that expectations for rates are generally priced in over a 7 day period, there is very little risk.