I'm not saying it doesn't happen, but it seems odd that a dog would actually bite someone because they didn't have a treat for them. That's not typically how a dog behaves.
I've been bitten a few times (all very minor), and none were because I didn't have treats. Generally, it's the little ankle biter that comes zooming up behind you without barking so you don't know it's there until it's latched onto the heel of your boot. Most dogs that are actually dangerous are also loud, so you have time to at least prepare for the attack.
There are actually only a few dogs that I give a treat to on a regular basis, and that's because they're such sweet little buggers. I've been caught playing with people's dogs in their yards thinking the owners weren't home. LOL... love dogs, but don't feed any that are "questionable."
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