Answer
In general, dogs in Uruguay are treated calmly and kindly. It is common to see people with pets on the streets, and a dog lying near a passageway does not usually provoke aggression or rude treatment.
In Montevideo, many establishments tolerate visitors with dogs, but this should not be understood as an absolute rule for every place. It is better to check the specific signage, the type of establishment, and the staff’s reaction.
For pet owners, it is more important to plan practical matters in advance: housing, a veterinary clinic, the pet’s usual food, rules for transporting the pet, and the dog’s behaviour in public places. A friendly environment can then genuinely make adaptation easier; it does not replace preparation. This is especially important when renting long-term.