of course it could. I'd think her odds would be much higher going for a person breeding good belgian dogs (Mal's) as I said before and just happening to get a longer coat "Terv" than somebody breeding specifically for them. I'm betting you probably agree with me and know this to be true as well.
Perhaps I've just met more quality Belgians of other varieties than you have. I've met many that I would LOVE to bring home! There are some spooks, but there are many that are happy, awesome pets. To be TRULY honest, I've seen a higher rate of outgoing personalities in the show bred Belgians than I have in the working bred dogs. How they would handle an attack may vary, but they are lovely social companions.
My own dog has a very strange temperament. He's hell on decoys, and very prey driven. But, he has some sort of social anxiety. If somebody that he doesn't know starts showing him positive attention, or doG forbid tries to touch him, he flips. When he was younger, it would elicit a major threat display. He's gotten better, but still has a shrinking violet effect. I have no doubts that if I were attacked by an aggressive person, he would engage whole heartedly. But if the attacker were to sweet talk him, it has the effect of Kryptonite on Superman. So if you ever need to attack me, keep that in mind. Keep telling Harry how beautiful he is while trying to pet him. Then you can get me while he's disabled :rofl1:
The thing is, I wonder how common this temperament is. In FR for example (since it's the one I'm most familiar with), there isn't a lot of friendly interaction with the dog with unfamiliar people. If a dog truly has this type of narrow spectrum social issue, the dog could still manage to get to high levels of competition. I've met many dogs that I suspected may have a similar temperament, and some of them were dogs competing at the national level. I can walk Harry though a busy crowd with no problems, and he has no noise or environmental issues.