The government doesn't need a backdoor. They can walk in the front door, ie, the open transaction ledger. Also, if a particular actor wanted to influence the course of any open-source project, he could simply join the project and contribute code (assuming some degree of subtlety in crafting pull requests, of course). The beauty of the process is that harmful contributions are weeded out, and if the worst-case scenario comes to pass, the project can be forked with a new lead developer.