Mine moved 1.5" rearward with 2 snowboards attached to it. It was extremely windy on the freeway and i noticed it when i got to Mammoth. I adjusted the factory bars when i parked the rav, and made sure it was tight. No issues going home.
I have Toyota OEM cross-bars with a 16L Thule box. Bars have never moved. Install them snug, checked after some highway driving. No problems. Go OEM as they've been tested to same high quality controls as rest of Toyota parts.
Was paranoid the first time I ran with rack on...but I've gained trust in it.
ReRack has a great deal on Yakima Whispbars. They are 50% off. I have them and they are low profile and quiet. I also like how they are secure and come with locks. Just know that they are low profile. Just it depends how much clearance you need between the roof and the bars for attachments. You will need the S54 for the 2015+ RAV4.