Pretendo already has some features that could cause unintended side effects anyways.
For example, the StreetPass Relay system is vulnerable to exploits due to the quality of the StreetPass parsers and that’s why it’s friends only: see StreetPass Relay FAQ.
Also, not sure if it was changed but Pretendo was allowing people to go online with older versions of games (so like you could go online with Mario Kart 7 1.1 and potentially put yourself at risk of being exploited through ENLBufferPwn) if I recall correctly.