Can't the Board just add a rule changing the pet restrictions in the docs? How about a new rule limiting the number of units one person or entity can own? We must go to the original docs to answer that. "The authority for the board to enact a given rule or regulation must be either expressly authorized in the governing documents or Declaration of Condominium or be reasonably inferred therefrom."
If your board has adopted a new rule prohibiting pets in contradiction to the docs you are under no obligation to find a new home for Spot. The law is specific about a board's authority and the process for limiting uses and rights. Merely adding a new rule to the old rules and backdating the document does not make that rule enforceable and it might expose the directors to liability. Targeting a specific owner through such methods is doubly dangerous. Cowboy directors, if you're reading this, you are encouraged to shape up and follow the rules. If you're in an association with a renegade board, you may want to point them to this post and to this one by Jean Winters, Esq.
"If honesty is the best policy, then is dishonesty the
second best policy?" _____Grant Williams