Just because someone may be on stuff that's supposed to help keep them safe, they don't KNOW if they're clean unless they test. And test MORE frequently if they've increased the incidence of 'less-safe' sex due to be on meds.  Decreasing/stopping testing just because you're on meds makes as much sense as not using your windshield wipers in a storm because you're wearing a seatbelt. *facepalm*

To get prep you have to be tested every 3 months. So id say the likelihood is that there is more testing going on.  

What great is that today its the safest the hobby has ever been, ever. Rejoice and go stick something in someone raw!