Even many dog resource people such as breeders, trainers and veterinarians caution against this game. This is partly a failure to discriminate between agonistic behavior (conflict resolution & defensive aggression) and predatory behavior. Also, many people have issues about witnessing intensity. Intensity is not aggression, however.
...No topic engenders such a wide range of conflicting advice than whether or not it is advisable to play physical-contact games with dogs, e.g., play-fighting, tag and tug o' war. Some breeders and trainers are vehemently opposed to these games, feeling they make the dog uncontrollable and more aggressive. Other breeders and trainers, however, feel frequent games make for a better companion. Certainly, there are pros and cons of doing almost anything with a dog and this includes roughhousing.
...Disadvantages
It is highly unlikely dogs become more aggressive by playing games with their owners. Quite the contrary, in fact; customarily, game playing builds confidence and handleability and promotes friendliness. Perhaps the so-called increase in aggressiveness would be better termed excessive rambunctiousness - play-chasing, play-growling, play-mouthing and play-fighting, i.e., the dog is over-friendly. Nonetheless, regardless of how friendly the dog's intentions, unsolicited rambunctious roughhousing; is often annoying and can be potentially dangerous. Human games and sports offer a good analogy, especially when the participants have been poorly; coached and/or the game is badly refereed. It is not the games - tennis, football, or ice hockey, which are at fault, rather potential problems come down to a matter of control. And so it is with canine games.
It is highly unlikely certain games have an intrinsic property to render dogs uncontrollable. Instead it is the manner in which the owner allows the dog to play the game, which influences the dog's subsequent tractability and willingness to comply. For example, many trainers incorporate game playing and the necessary teaching of a multitude of game rules to reinforce their control over the dog. Alternatively, allowing a dog to play willy-nilly, without instruction or guidance would no doubt make him more difficult to control. Control-problems are threefold:
1. the owner allows the intensity of play to increase to the point where it may be physically dangerous
2. the owner can no longer stop the dog form playing and
3. the owner allows the dog to initiate unsolicited play sessions. The owner barely knew which end of the whistle to blow.
So, why not just stop playing these games altogether? Well, a good class instructor quickly learns to anticipate a lot about dog behavior and a whole lot
more about human nature. Firstly that dogs, especially adolescent dogs, are going to attempt to play this way with people anyway. In fact, much of a dog's waking existence and certainly most of his playtime focus on mouthing (and/or biting) objects both inert and alive. Consequently, it makes sense to take time to teach the critter rules. And secondly, that many owners, especially men and children and extra-especially boys (ranging in age from two to fifty-two years old), are going to play these games with dogs anyway. And so, it similarly make sense to teach owners how to be better canine coaches, so they may correctly referee Rover and reap the many benefits these games have to offer
...Advantages ...
When played according to the rules, these games:
1. increase the level of control owners have over their dogs, specifically proofing control at times when the dogs are excited and worked-up and
2. motivate, build confidence and make the dog less aggressive, specifically improving and maintaining his bite inhibition.