The US does not have the same level of privacy protection for personal information that either Canada or the EU have and the sharing of personal data has always violated the privacy laws of those countries.
Regardless, the Five Eyes have been used to circumvent domestic regulations on surveillance of citizens by using other countries of the alliance to intentionally spy on one another's citizens and sharing the collected information with each other. It has essentially been the outsourcing of domestic surveillance. Once that door has been opened, I highly doubt it can be shut. I also do not believe the international agreements/protocols in place have been complied with either.
A really good (academic) article about international data sharing may be found here if anyone is interested.