There is a third way. It's the same principal as removable magnetic lights in that it's removable. But it does require having a hitch on your vehicle, either a 1 1/4 or 2 inch receiver.
What I did was:
Purchased an Allen Sports Delux Hitch Mount 2 Bike Rack, $80 on Amazon
The carrier uses a 2 part square tube assembly, I used the bottom part that curves up from the hitch. The top of the tube is just level with my Subaru's tailights.
To the top of the tube I mounted a 4 foot long piece of aluminum angle using some stainless steel self tappers. At the end of the angle I mounted some led waterproof trailer lights, the kind you would use to replace the lights on a boat or cargo trailer. About $45 at Lowe's (where I work)
From there its just a matter of wiring everything up. Bought a trailer replacement wiring kit aqnd a few xtra plug ends. Wiring from the tailights runs down the tube and ends in a plug at the hitch. Ran wiring through the car, whih plugs on both ends. The rear plug plugs into the light, the front will plug into a disconnect at the front.
Basically I unplug the lights at the back, pull the hitch pin and remove the light assembly. At the front I will just unplug the harness from the front plug which will be attached to the base plate.
It sounds complicated, but it's not. Took me about 3 hours to rig up, but I like things neat so I took care to hide all the wiring, solder all the connections and cover the exposed wire with conduit.
Takes all of 1 minute to connect or dissconnect the two plugs and pull or mount the rack.
No scratches on car from magnetic lights or wire running across the car.
Grumpy