You can tow one ATV with a very light(Aluminum) 500 lb trailer.
I think you needed the V6 RAV4 with towing package to safely tow a pair of ATV's. I know these can tow likely 3500 lbs given the trailer I borrow from a V6 RAV4 owner.
Toyota says 1500 lbs, there is a very good reason for this. The problem isn't weather or not the RAV4 will pull the weight, the problem is STOPPING
(as others have stated),
Indeed, although IIRC the front brakes are the same between I4 and V6. I think rear brakes may be somewhat larger, but it's been too long.
I don't think trailer brakes are that expensive to add. I think I looked into once and it was like maybe $300. But it's been a while. Oh and then you need the brake controller. Anyhow. This has less to do with the tow vehicle and more to do with the trailer -- I'm not sure how people can sell trailers with GVWR just under 3k without brakes. I know NH state law "allows" my Tundra to tow that much without brakes, but still. Seems sketchy.