The demand is not limited to owners of large amounts of Bitcoin or to those who have transacted in large amounts. Everything about everyone. Equally shocking is the weak foundation for making this demand. In a declaration submitted to the court, an IRS agent recounts having learned of tax evasion on the part of one Bitcoin user and two companies. On this basis, he and the IRS claim “a reasonable basis for believing” that all U.S. Coinbase users “may fail or may have failed to comply” with the internal revenue laws. If that evidence is enough to create a reasonable basis to believe that all Bitcoin users evade taxes, the IRS is entitled to access the records of everyone who uses paper money. Anecdotes and online bragodaccio about tax avoidance are not a reasonable basis to believe that all Coinbase users are tax cheats whose financial lives should be opened to IRS investigators and the hackers looking over their shoulders. There must be some specific information about particular users, or else the IRS is seeking a general warrant, which the Fourth Amendment denies it the power to do. Speaking of the Fourth Amendment, that rock-bottom “reasonable basis” standard is probably insufficient. Americans should and probably do have Fourth Amendment rights in information they entrust to financial services providers required by contract to keep it confidential. Observers of Fourth Amendment law know full-well that the “third-party doctrine,” which cancels Fourth Amendment interests in shared information, is in retreat. The IRS’s effort to strip away the privacy of all Coinbase users is more broad than the government’s effort in recent cases dealing with cell site location information. In the CSLI cases, the government has sought data about particular suspects, using a standard below the probable cause standard required by the Fourth Amendment (“specific and articulable facts showing that there are reasonable grounds to believe”). https://www.cato.org/blog/irs-believes-all-bitcoin-users-are-tax-cheats
