Testing is a problem though isn’t it? I contracted Covid because my elderly mother who we are in a bubble with, fell and was admitted to hospital. She was tested twice 72 hours apart, and was said to be Covid negative. She was discharged home. The next day my husband popped into her flat to do a small job. Mum was feeling ill and the carer had rung for an ambulance. My husband was with Mum for 40 minutes only. He was wearing a mask and so was Mum. But when she arrived at hospital it was found she was actually Covid positive, acquired in hospital. Meanwhile my husband had contracted it from her, and he brought it home to me. I was the only one out of the three who was seriously ill with it. So my point is that testing isn’t always reliable, and that’s a big problem for all countries asking for a Covid negative test before arrival.
My son in law also contracted Covid from his work, he is a medic. Although he was ill and suffering symptoms, the first two tests said negative. Only the third test showed positive. Testing just isn’t reliable enough, quarantine in a hotel, or more rigorously enforced at home is the only answer.