Those of you who are saying that they wouldn't mind as long as their family wasn't high risk are missing the point of this lockdown. You don't get to make the decision that you and your family are comfortable with the risk of catching covid because you don't exist in a bubble. If you catch it you become a risk not just to your household but to everyone you interact with, everyone you pass on your daily exercise, in the supermarket, etc.
You may have seen people talking about the R0 number - the average number of people who are infected by every individual who catches covid - which can only be brought down by everyone minimising their chances of catching it and/or passing it on. And because you don't necessarily know when you have it, everyone needs to try and minimise those chances all the time. Everyone, including you.
Say you caught it on one of these visits, and were confident it wouldn't get passed on outside your household because none of you are working (at all) , or going to the shops (at all), or exercising outside the home (at all) and literally the only people you are in close proximity to AT ALL are your own household and the family members you invite to the house: you are STILL increasing the overall danger to others.
Because if, god forbid, you are one of the unlucky ones who ends up in hospital, you're then increasing the risk for every other patient and member of staff.
It's unlikely, sure, but every single small choice that we make at the moment has the potential to increase or decrease the likelihood of these things happening. So if it isn't essential, you should always make the choice to decrease risk for everyone's sake.