I'd say it's great that they're so friendly, and I wouldn't discourage such trust, but would say that they probably need to be protected.
I would definitely advise extreme caution with any dogs that you aren't absolutely positive are gentle with cats. I love dogs and have 3 of them (all good with cats), but it's important to keep in mind that even a small dog can kill or seriously injure a cat in the blink of an eye (think about tiny rat terriers, and dachshunds, bred to kill badgers). They have very strong jaws, and can move incredibly quickly if they're stimulated to hunt or attack.
If they're not at all afraid of dogs & will even run right up to a Rottie, than it's probably better to keep them entirely indoors, except when you can be right there with them, & close enough to grab the cat & move to a safe place if a dog comes by (it's not unknown for a dog to jump at an animal in a person's arms, either).
If someone is visiting your house with a dog, put the cats up unless they assure you that the dog is cat-safe. If the dog owner says the dog is OK with cats, have the owner keep the dog leashed while you both observe the interactions between the animals until you feel comfortable. Watch both animals carefully for any signs of tension. Some dogs might be fine with their own cats, but view strange cats as prey. Another thing to be aware of if you're visiting someone with dogs (or vice-versa) is to pick up the food dishes - some otherwise friendly dogs may behave possessively around food.
My cat Felixia isn't afraid of dogs at all either, so if I take her out in the yard, I do it on a leash & stand right there with her to pick her up & go inside if I see a dog coming.
Hope this helps