YSK: Deer and rabbits "park" their babies and spend most of the day away from them. If you find a baby all alone, it is almost definitely not abandoned.
Why YSK: DON'T bring it somewhere to 'save' it unless it's in immediate danger - you're probably just kidnapping it from its mom. People find baby deer or rabbits with no parents nearby and think they're abandoned, so they bring them to shelters to try to "save them". In reality they're just forcibly separating the animal from its mother and greatly reducing its survival chances.
Infant rabbits without their mothers don't do well. Even in professional care settings, they have about a 90% mortality rate. Taking them away from the nest should be a last resort, only when death is guaranteed otherwise.
To piggy back on this, you can touch "baby" animals. The mother will not leave them. If you disturb a nest, den, etc, place the young back to where they came and the mother will come back,.