With all do respect - I disagree. The pictures posted are not from the same angles and distances from the camera as the ones in this post (not to mention the appearance of that gap changes significantly with respect to camera angle). In addition, that urethane and metal are going to contract/flex/expand at different rates - it might look good for a little while, but probably won't last a substantial amount of time. Cracks are going to form and that paint (clearcoat and maybe basecoat) is likely to start to flake. The color of the stripe and the car is also likely to play at least a small role in the optical illusion in the gap of the stripe too. A darker car will hide the gap better while the opposite for a lighter color. Likewise for the color of the stripes. The only way, to my understanding, to get this to work on other gaps between the panels on the car (i.e. like fenders, doors, quarter panels, hood and trunk gaps, etc.) would be to backtape or use something like 3M™ Soft Edge Foam Masking Tape; neither of those would likely work or be practical in this specific instance though.
The bottom line is, the correct way to paint a bumper cover, to insure complete clearcoat coverage, is off the car, just like at the factory. They don't paint the car with the bumper covers on - at least in any shot I've ever seen. I-Car, Tech-Cor, PPG, Dupont, and others say this too to my recollection. There's just not enough room to get the paint gun in the gap to get the clearcoat around the edges.
Or, go to a bodyshop that does quality paint and ask them what the correct way is, and how that paint would lay down in that gap if the facia is left on there. If you ask me, and how I wrote things (and even how insurance companies wrote things; and yes, FWIW - I worked at a bodyshop for more than five years and a dealership five years before that, writing estimates and controlling repairs on all my customer's cars) one might find an agreement with me. But I digress...
I'm sure Tag' and THR have worked all of this out
I didn't mean to sidetrack, but I think there are some things to think about and consider
