In the Channel Islands we closed our borders right at the start. We've had no sea or air travel available to us as residents (unless it's for a Channel Island government-approved sanctioned emergency reason) and no one coming in, unless they were one of the very few stranded abroad in the early days. Even then, it was very difficult to get back. We've also had clear time limits on going out every day (2 hours a day at first, then 4 hours, now 6 hours) and what we can and can't do (but we've been allowed to swim in the sea, or go surfing/paddle boarding as long as the rules are obeyed - and, mostly, they have been).
Subsequently, our numbers are much lower than the mainland's per head of population (only 1 new case confirmed in the last 9 days, and a run of 6 days with no new cases at all) , and no care homes/nursing homes have seen the virus take hold and run riot. Yes, there have been isolated deaths in several care homes, but the odd 1 here and there, not running rife like the UK.
In Jersey we've just opened pubs and restaurants for outdoor eating (compulsory advance booking, with what we're calling 'physical distancing' here applied, and anyone sitting at a table must be from the same household). Our bigger 'non-essential' shops can also open this week (so we can buy clothes and household items) and if that all goes well, we'll continue opening up the island to ourselves. Schools will look to start opening to more pupils on June 1st (one of my DCs works in a school, so has been at work throughout anyway)
But we can only continue to do make these strides forward if we keep our borders closed. As residents, we're worried that as soon as they open, the virus will flood back in. That the UK government will press for us to accept business and leisure travellers from the mainland, and our government will want to do the same, while many just want to go 'full New Zealand' and keep borders closed for at least the next 4-6 months, or until the UK catches up with us. The mainland's policy just looks a mess from where we're standing (and no one on mainstream news refers to how the Crown Dependencies are doing, so we feel even more isolated!).
Our tourist season is already negated for this year, so we won't lose much from closed borders than we've already lost. It's tough on us, because being trapped on a 9x5 piece of granite for months on end is not much fun. Our economy, internally, in the absence of visitors, needs us to open up internally and kick-start ourselves, but without the risk of the virus being imported through our borders. The UK needs to do the same, but it can't while its rates remain so high because it's lost its grip on who's coming in and where they're going when they get there.
Usually, people here yearn to 'get off the rock' at least 1-2 times a year, if not more! You need to for your sanity (everyone knows everyone - or, at the very least, someone knows someone you know!) so the isolation is hard right now. But worth it.
75 years ago the German occupying forces left our islands after we'd been abandoned by Churchill to fend for ourselves in the face of the Germans advancing our way. We survived then, and we'll survive now. We saw off the German occupying army (who were all starving, along with the rest of the islanders, by the time Liberation Day came on May 9th 1945 - D-Day was a good thing for everyone except the Channel Islands, as it cut off what meagre supplies the island had been getting) and we'll see off this virus.
But we don't want to invite it back in any time soon, and I really feel for my family members on the mainland who are in despair at the lack of decisive action about border security and compulsory isolation for the thousands of people who continue to arrive by plane into the major airports.
Too little, too late, Boris. And that's without the ongoing confusion he seems to have kicked off yesterday about what you can and can't do! Watching the Coronavirus update this afternoon will be fun... 
