You never know! While in hospital a few years ago, I watched the old boy in the bed opposite get his pre-op check from the anaesthetist. "Are they your own teeth?" he was asked.

Looking highly indignant, he answered: "Why, aye, of course they're my own."

Turned out, of course, they were dentures. But they weren't anybody else's dentures.

Luckily, the misunderstanding was discovered before he went for his op.