And no, it is not bad etiquette to say, "no pets allowed." your house, your rules.

并且说“宠物勿入”也并不是什么不好的礼节。你的家，听你的。

youdao

230the following appeared in the Sherwood Times newspaper. "a recent study reported that pet owners have longer, healthier lives on average than do people who own no pets."

230一项最近的研究报告说养宠物的人平均而言比不养宠物的人活得更长更健康。

youdao

The country's only public defender of animals, Mr. Goetschel is a vegetarian who has no pets and avoids taking medication because of his opposition to research on lab animals.

作为瑞士唯一一位动物权利公立辩护律师，哥切尔是一名素食者，没有养宠物，因为反对动物实验，所以尽量避免吃药。

youdao

I feel no superiority over my beloved pets when I look at them in the eyes, and eventually after they lived with me long enough to communicate Fortunately I don't expect them to take my courses.

当我看着我深爱的宠物时,我并不自以为比它们高等，就算后来,我们一起生活很久，都能相互交流了,所幸我并不期望它们来上我的课。

麻省理工公开课 - 电影哲学课程节选

As you suspect, the general rule is that you cannot keep out anyone who needs such an animal, even in a no-pets building.

WSJ: Should 'Support Dogs' Be Allowed in No-Pets Buildings?--WSJ House Talk

"Battersea is now receiving calls every day from animal lovers who feel they have no option but to give up their cherished pets because they can no longer afford rising vet bills, they've been made redundant, they've been made homeless, or face imminent eviction, " it said.

BBC: Credit crunch 'prompts abandoned pets rise'

The zoo manager stressed that it was no threat to any domestic pets it may cross paths with.

BBC: Coati missing from Belfast Zoo thought still alive