Two things (maybe three):
1) The parts that hang down to keep the bikes from swaying are not attached when you receive the rack. You push the part onto the already-mounted hanger and rotate it down to keep it in place. This keeps it from falling off when in use. Unfortunately, when not in use, a rotation of the anti-sway part (either by the wind or when mounting another bike) can (and DID!) cause the anti-sway part to fall off. To prevent this from happening by accident when the rack is not in use (or some of the bike positions are empty), I attached the rubber strap that is used to secure the bike to one of the attachment knobs on a part that can't fall off. This works for all but the bike position closest to the car trunk. That anti-sway hanger has TWO pieces, both designed to fall off in the same way. With no alternative, I now just take them off the unit entirely and store them in my trunk when not in use. This is not at all convenient, and I'm guessing that eventually I will just stop using the anti-sway pieces for short trips.
2) I would have bought the 2-bike model, but I decided to buy the 3-bike unit because there is only 4 inches between hanging positions. As I suspected, the rear rack on one bike gets in the way of the handlebars on the other. So I mount the bikes in position 1 and 3, leaving position 2 empty. This works fine, except:
3) Thule specifies that this 3-bike rack, which is sold in a 1.25" hitch version., should not be used with 3 bikes in the 1.25" version. Really? Why even sell a rack that's not supposed to be used in the configuration it's designed for? Besides, isn't the total weight on the hitch what really matters? 100 pounds or less should be the criterion, not the number of bikes on the rack.
4) Just as a point to consider: The product information for the 1.25" hitch I have warned that one should use a support/stabilization strap (available from U-Haul for around $9) when using a rack (vs towing). Seems like a good idea to me.