I bought my place off the plan. Was there for the first AGM where we decided our by-laws – including pets. Our SM advised us to allow pets within reason (ie not large dogs). SM said that to say no could lead to a long drawn out battle and best to allow small animals. So far no problems and being pet friendly seems to be a big selling point judging on how fast places here sell and usually for above asking price.
So if you buy off the plan you don't know what the pet policy will be until it is in place. You could be buying into a complex of people who don't want to have pets like downsizers – don't want lawns or pets to take care of anymore. Or professionals who simply do not have the time to take care of a pet.
If you already have a pet, could be risky. But if you don't, you could see how things go and put your two cents worth in at the first AGM. Let others see that though they may not want pets, when they sell in the future the next owner might.