I think I should add something here for anyone who decides to follow me off this cliff...one possible minor challenge/disadvantage?

Remember when you expose that tab, you are also removing 50% of the retaining strength that holds the metal insert inside the plastic socket. So when bending the tab out, you need to give some of the strength back to that connection, to keep the socket insert fully seated. With this in mind, make sure you create a nice clean bend as far up the tab as possible, make sure the socket insert is stuffed as deep as possible while making the bend, and bend it out far enough that the new bend is actually providing the strength needed to keep that socket insert bottomed in the plastic socket (it seems to me that about a 45 degree bend is best...a little more bend than shown in my "finished" photo above, which wasn't really finished at all because I hadn't heat-shrinked the crimp connection yet...also highly recommended). If you let the metal insert walk up too high and leave it loose, you run the risk of losing connection for the 2 electrical contact points at the bottom of the bulb because the bulb will sit too high.

A nice tight spade connector shoved on as far as humanly possible also contributes to keeping the socket insert bottomed tight.

And I still may dab that connection in liquid electrical tape or silicone or similar which probably would add a little more security. Or I may not. It is a dry connection in a protected area...not worried about corrosion.

I believe it will hold very well indefinitely, unless wiring is bumped or manhandled repeatedly inside the trunk. But obviously you're going to need to check back with me in about 10 years for a longevity report...since my crystal ball is in the shop right now...

AND...for someone who REALLY wants security, it would take about 5 minutes to drill a small pilot hole thru electrical connector/tab and into the plastic socket body, and run a short screw into the hole, inteconnecting all three, to make this a truly secure electrical connection AND keep the socket insert bottomed fully forever, which will also resist all accidental trunk-bumps...in fact I am very likely to do this before messing with liquid electrical tape or sillycone...screws are cleaner and easier to remove if future disasssembly is needed.

And keep in mind...if this whole project doesn't work for someone else for whatever reason, or you screw one up while cutting/bending it? Replacement sockets are what, 5 bucks? I don't see a lot of risk here other than slicing tendons in half with your utility knife while whiddling the plstic...be careful!!!