As an arch user, I would always skim the PKGBUILD file of AUR packages to see if they install the software they claim to install from official sources and if there's something obviously fishy.
Jokes aside and just in case, you do realize ports and AUR have two very different models? Ports is more similar to the official Arch repositories, which obviously doesn't suffer from the same problem, and AFAIK, there is no BSD-equivalent of AUR.
BSD is cool and useful for lots of reasons, but comparisons based on misunderstandings helps no one :)