...because VPNs obscure a user’s true location, and because intelligence agencies presume that communications of unknown origin are foreign, Americans may be inadvertently waiving the privacy protections they’re entitled to under the law...
...VPNs might protect you against garden-variety criminals, but the intentional commingling of origin/destination points by VPNs could turn purely domestic communications into “foreign” communications the NSA can legally intercept (and the FBI, somewhat less-legally can dip into at will)...
Certainly the NSA isn’t concerned about “incidental collection.” It’s never been too concerned about its consistent “incidental” collection of US persons’ communications and data in the past and this isn’t going to budge the needle, especially since it means the NSA would have to do more work to filter out domestic communications and the FBI would be less than thrilled with any efforts made to deny it access to communications it doesn’t have the legal right to obtain on its own.
Since the government won’t do this, it’s up to the general public, starting with everyone sharing the contents of this letter with others. VPNs can still offer considerable security benefits. But everyone needs to know that domestic surveillance is one of the possible side effects of utilizing this tech.