Exposure notification help

[Lifestooshort1542]

My friend received a notification today saying to self isolate for 8 days, and on the app it's saying the exposure was two days ago, she was swimming and then had lunch but never scanned in to check in at the cafe so how has she received this exposure notification? Would it be someone in the cafe who's tested positive and the app has picked that up on her phone nearby while she was in there too?
I was with her but I haven't had a notification!
I'm worried and confused.
How does the app alert you if you haven't done a venue check in? I'm trying to figure out if I could have been exposed too.
Thanks and please be kind ☺️
Merry Christmas!

It works on Bluetooth so not just from checking in. It Will measure distance between phones and length of time you were close to them.

If you were further than 2 metres away from the person and she wasn't (depending where you sat in the cafe) then you wouldn't get notified as a contact

Did she leave her phone in a locker while swimming? They do suggest that you switch off your Bluetooth if you leave your phone unattended to avoid prolonged contacts with other phones.

@Angrymum22

Did she leave her phone in a locker while swimming? They do suggest that you switch off your Bluetooth if you leave your phone unattended to avoid prolonged contacts with other phones.

Yes! She did and I didn't I left mine in the car! That's a really good point I hadn't thought about that thank you for taking the time to reply. So it seems like two phones were nearby for an hour (swim slot time) and that's why she was notified? Would you still isolate for this even if you weren't in contact with the person?

But she might have been close to someone in the cafe too

You can’t really decide that her phone picked up someone else’s signal from the locker because there’s no way to know that for certain. If you have the app then it’s part of the deal that you isolate if it alerts you.

It’s shitty (DP has two days left from an app isolation and no clue who it could be) but it’s trying to achieve something that you’ve agreed to when you’ve downloaded it.

It’s definitely made me more conscious of keeping at least 2m away from people.

I think she would still need to isolate but it may explain why she was notified and you didn’t get the notification.
I think if it was a contact in the cafe you would both get the notification.

But OP left her phone in the car or did she go and collect it before going on the cafe?