How is it possible for some one to go that long and not get caught, multiple times?
Well the poster of the picture is in Oregon if you believe their location listing. So maybe the car is down in Oregon and the Oregon cops just aren't paying that much attention to the year sticker. However, rpo did say that the car was regularly crossing 520 which tends to point away from this theory.
Regardless of all that it's actually probably fairly easy for someone to get away without a valid plate for a long time around Seattle. Lots of traffic, not a ton of cops and they're often busy dealing with accidents or other significant incidents. The stickers are only on the back so you have to have a cop see the rear plate and notice the sticker, which practically requires being right behind you. I'm also sure that expired registrations are low priority enforcements for them.
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Saved the image and took a look to see if there's any metadata. There isn't. So can't tell what date or where the picture was taken. It also looks to me like there's another plate under the OHM plate based on the non-aligned bottom holes. Very interesting mystery.