Can someone answer a question about the app

[Layladylay234]

My mum is freaking out as has had a message saying she was in contact with a positive case (date of exposure 1/1/21). I've read up and it seems the message would have been sent out in the following circumstances:

She checked in somewhere and someone there tested positive
She was within 2 metres of someone for 15 mins or longer

The only place she went on that date was the small Co-op up the road. She didn't see anyone. So unless she was being followed by someone/following them around the shop, closer than 2 metres, for 15 mins (unlikely!)....it can't be there can it?

I've told her the likelihood is one of her neighbours as shes in a row of terraces.

Is all this right? I'm trying to relieve her worry as I think she's concerned she's got covid from the guy she buys the newspaper from at the corner shop/caught it when someone walked past her when she was walking the dog. Despite me telling her the algorithm only sends messages for 15 mins min and within 2 metres.

I think it’s supposed to only send the message if it’s been 15 mins/less than 2 metres however I know of at least 3 people recently who have been told to self isolate and they are adamant that they have only mixed with their own family group, none of whom have tested positive! One friend has to self isolate because his next door neighbour tested positive even though he has not socialised with him at all!

I’ve also heard stories of people in flats having to isolate if another person in the same block is positive - madness!

Yeah, I'm convinced it's one of her neighbours and am trying to reassure her of this.