The only time I take mine in where its questionable is when I'm already out and need to stop somewhere. I used to take her to work with me, and since I didn't get off until 5:30 or 6:00 pm, sometimes, going the whole way home, dropping her off and running back out, when I only had to grab a couple of things at the drug store...well her carseat doubles as a carrier...it was just easier to take her in with me.
Leaving her in the car is not an option. I'd never forgive myself if something happened to her!
When we're traveling, we look for restaurants that allow dogs on their patios - just ask, there are more than you think - and places where she's allowed. I usually research the area we're heading to (or through) and located dog parks, parks where dogs are allowed, and activities where they are welcome. For example, we spent some time at the finger lakes in NY last year. While we left her in the home we had rented for much of the time, we also took her along to several wineries (not sneaking), to an indoor/outdoor flea market that welcomed pets and found a bike trail where we could spend a day riding (with her safely ensconced in her basket). But sometimes, you're in a pinch, and you've gotta do what you've gotta do. I've never taken her into a grocery store or restaurant (except as explained above) but have seen another yorkie in the grocery store once.
Regardless, I think dogs should be allowed more places. BIG DOGS AND SMALL DOGS. In some parts of Europe, they're everywhere, even restaurants!
One of the best things you can do for your dog is socialize them, and that's hard to do when it's NO DOGS ALLOWED.
