What's the chance of someone who was adopted meeting a sibling?

By this, I mean someone who meets a sibling and they don't know it. The two siblings just live similar lives close to each other so they run into each other.What's the chance of someone who was adopted meeting a sibling?
I actually met my half sister nearly a year before I met her officially.......we both lived in the same town. Neither she nor I had any idea that we were sisters, despite the fact that I looked like our mothers twin.........when I met her officially for the first time, the day I spoke to our mother for the first time, her first words were "oh my God you look just like Mum!!" Later on, after we had both calmed down a little, I brought my pet weiro (cockatiel) into the house, as a rule the bird was always on my shoulder, she literally went everywhere with me, including the shops. My sister said "I know that bird!" and then we twigged that she had approached me in the shopping centre and had a long chat with me, about the bird.....all the time never noticing that her long lost sister was the one with the bird on her shoulder.......I can understand that, the bird was totally adorable!!
If they live in the same town it is very possible. But it depend as well on the age groups. I have often heard of funny stories about this. Or even serious ones where they date and don't know they are related until they meet the families.What's the chance of someone who was adopted meeting a sibling?
That is always a possibility. My oldest son did just that and Mom's new husband called here and I told him my phone was being monitored.
Higher than most people think. There are many cases documented of sibling attraction.What's the chance of someone who was adopted meeting a sibling?
My last foster son had 27 siblings %26amp; half siblings under 14 years old in a town with 12,000 people....that we know of. Chances are so high they have to be careful who they date in school!