A Defense of a Paulson-esque Plan that I Hadn't Come Across

A Wall Street friend of mine made the following point: one advantage of a government purchase of toxic mortgage-backed securities over an equity infusion (which apparently most economists support) is that the government can hold these assets to maturity without having to worry about being margin called. This matters because banks aren't the only entities holding lots of crumbling paper; hedge funds and other non-bailed-out institutions are likely to make forced sales of MBS, further driving down their value. Consequently, banks would require more and more capital from the government in order to stay afloat -- probably more than the government would initially overpay if it bought MBS and then received an equity "true-up." My friend argues that the absence of this idea from mainstream discourse stems from economists' underappreciation of the interconnectedness of the many players and games that caused the financial crisis. Contagion is a serious concern; perhaps an equity infusion is a mere treatment, whereas a Paulson-esque plan constitutes a quarantine.

UPDATE: this is not to suggest that my friend or I believe that a Paulson-esque plan is overall better than an equity infusion, just that the above reasoning may be part of the method to the madness.