If my understanding is correct, you can simply drive around with the hubs locked in, then shift into 4wd whenever you want. It's just like having auto hubs. The downside, of course, is that you're still spinning parts you don't need, dropping your gas mileage, and putting unnecessary wear on your CV boots.

Maybe you could convince her to compromise; leave the hubs unlocked when you know you won't need them (during the summer or on road trips, for instance) and locked in when you might (winter driving or 4wheeling trips).

'98 Rodeo, Ranchos, OME 912s, General Grabber AT2 265/70/16s on steelies, Superwinch hubs, G80 code, Pioneer HU... two car seats and cracker crumbs.
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Illegitimus non carborundum.
Educatio est omnium efficacissima forma rebellionis.