It’s possible but I doubt it.Will they actually check that people have the app though?
There were reports of pubs and restaurants refusing entry unless you could show the app and check-in - but it isn’t a legal requirement as you can supply details other way.
https://www.dailymail.co.uk/news/article-8785123/Customers-embarrassed-young-arrogant-bar-staff-Covid-app.html
The bigger problem with the app is you can’t checkout, you are leaving up to the team to decide if you were at risk or not and whether they contact you.