unless we have a way of protecting this? did not think so.
That's not how open markets work.
Many people wouldn't sell their bitcoins for such a low price. As the government bought up the available bitcoins, the price for the remaining ones would continue to rise (due to the surge in demand with limted supply). The increasing exchange rate would cause many other people to buy bitcoins hoping to make money on the rising exchange rate. This would drive the exchange rate even higher. It would quickly become prohibitively expensive for the government to buy all the bitcoins in existence (especially since 25 more bitcoins are being created every 10 minutes.
Meanwhile all the people holding bitcoins would make a lot of money on the huge investment bubble that would be triggered. Eventually the bubble would pop, and the price would come crashing back down. All those that made large amounts of money would have the opportunity to buy even more bitcoins at the new extremely low price.