I was following a thread and was amused by some of the answers. I'm interested to see how much people know.
I think no one will know that you have your own bitcoin unless you will share it to them, what I mean is that you tell them about it. Also if you secured it and place it in a cold storage well expect that no one will know it. Just be wise and responsible on bitcoin you have.
Yes, it is hard to know that you have own bitcoin because blockchain is a decentralized system and no third party knows you have that kind of transaction, even if someone intentionally search but still they don't know the person behind the wallet address.