Does a symbol have to be unique in ERC721? How to find out a unique symbol?

Question

As per the ERC-721 contract on OpenZeppelin, you can create a token with this constructor:

constructor(string _name, string _symbol) public {}

Does the "_symbol" have to be unique across the blockchain? If yes, then how can one find a unique public _symbol? Is there a public register maintained?

If it doesn't have to be unique, then a duplication of a contract with the same name and symbol, won't it confuse the people searching for your _symbol?

Answer 1

Does the symbol have to be unique across the blockchain?

No, the only thing which needs to be unique is the contract address.

If it doesn't have to be unique, then won't it confuse the people searching for your symbol?

Yes, that's why it is in your interest to choose a unique name and a unique symbol.