1050.9(h)1 of the MTA Rules of Conduct states:
[…] no person may bring any animal on or into any conveyance or facility unless enclosed in a container and carried in a manner which would not annoy other passengers.
Redditor spuddyh3ll recently spotted this sleepy Boston Terrier, not annoying anybody, and clearly in a backpack, thus, s/he is a perfectly legal and well-behaved subway dog.
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