It depends on the quality of the question.
My pet is injured, what should I do?
If the obviously only viable answer is "go see a vet" then we should close the question. The help center clearly states
Emergency medical situations may be accepted on this site provided one or more of these conditions may be met:
There are potential emergency measures that may need to be taken care of prior to bringing to the vet.
There is no possible way to seek professional veterinary care at this time.
The situation is, ultimately, preventable and that it is possible to provide some advice on avoiding the situation in the future.
The logical consequence is that questions that do not satisfy any of those requirements are off topic.
That means that questions like "My pet got hit by a car.", "My pet is suddenly acting strange after an accident" or "My pet ate an obviously harmful substance" are clearly off topic because the situation was not preventable and there are no emergency measures we can offer without much more information from the OP.
The added (positive) effect of closing such questions as fast as possible is that the OP doesn't waste any more time waiting for answers...
Sometimes people are just insecure and need someone to tell them what to do. Unfortunately they tend to ask the internet instead of a specialist. Closing a question instead of leaving it open without answers hopefully gives it an air of finality and makes the OP redirect their question to a vet.
An example of such a question is: Cat doesn't eat anything and shiver sometimes
My pet has this specific injury, how can I treat it?
This kind of question may lead to a single answer stating that only a vet can treat the injury, but it could also get answers of first aid measures or home remedies.
In my personal experience, if the OP described the problem or injury in detail,
- the quality of the question in general is good enough to deserve an answer.
- the question satisfies at least one requirement to be on topic.
These questions should be left open even if the only answer is "go see a vet".
An example of such a question is: Dog has eaten plastic 'doggy' bags