First- Suppose we rephrase this as: "How UNSAFE is it to allow my cleaning person...." That could have a helpful effect of reducing bias towards an answer you really want. And I'll present a Risk Analysis paradigm to help YOU decide for yourself. Note that I am NOT a biologist or otherwise a professional life scientist. But this is why you are on this forum- to get advise from a professional like Erin Bromage. Note that I will NOT think for you.
Second- What is the hazard? Covid infection.
Third- What is the downside RISK if the hazard is realized? If the risk is as mild as catching the common cold, then assuming no one in your circle is otherwise vulnerable, then so what? Ah, but we KNOW the risk is death or severe injury secondary to the infection. Perhaps cardiomyopathy, perhaps irreversible lung damage, perhaps a heart attack or stroke secondary to damage to the endothelial layers of your arteries and veins ,perhaps some other horrific outcome. "But I'm young and healthy, it won't happen to me." Two Words- Optimism Bias. But supposing you really won't have a symptomatic course of disease; many don't. But you are still shedding virus like many asymptomatic people. Ok, so what is the value of not accidentally infecting mom and dad? Grandma and grandpa? Your sister the cancer patient? Your cousin who is immuno-compromised for any number of reasons from AIDS to steroid therapy? Or your toddler with aplastic anemia? Now suppose NO ONE in your immediate circle gets symptoms (but they ARE infected). Given that, how about their friends and loved ones? Suppose an infected person visits a skilled nursing facility? We have documented case after case of infection spreading like wildfire in SNFs and killing every other resident. (That's an awful lot of collateral damage.)
Potentiating the risk- How confident are you in your housekeeper's competence and willingness to NOT spread? If he/she's a grad student in microbiology making money for textbooks or the equivalent, then the risk is greatly reduced. If the opposite is true.... Oh boy. Does your housekeeper have an economic incentive to be extremely careful, such as a doctor might be careful, or is the incentive to get in and out as quickly as possible- say perhaps because the person is paid per job instead of per hour? Economic incentives DO drive behavior. Just look at PG&E and the fires their mismanagement has caused. Look at Enron. Look at Bernie Madoff. We all know this is true.
Fourth- How do you mitigate the hazard? This could be anything from doing nothing to barring the door and not allowing guests. Period.
Finally, why would you- the prime stakeholder- abdicate your power to decide matters of life and death for your family? Why would you allow someone with NO stake- ZERO- in your health to make this decision for you? What is the BENEFIT of having the house cleaner? (Benefits are a factor too.)
I sincerely hope this does you and your family some good.
Edit 6/16/20: Here's another question for you or *anyone* similarly situated: If you have to wipe down counters, floors, high-touch areas like door knobs, light switches, refrigerator door handles, the toilet and faucet handles, etc. AFTER the cleaner has come and gone, how are you ahead? If you take 3 hours away for them to do their work, and then an hour to decontaminate your house, didn't you just expend the time you originally liberated by hiring it done? What's the value of not being made anxious by the housekeeper's presence?
While it's true that many could decide to proceed, many others might not. It's everyone's own personal choice.
For related information on Risk Management, look up the topic and/or look up "Aeronautical Decision Making." ADM is CHOCK FULL of information on risk analysis for anybody in the aviation industry from private pilots to air traffic controllers to jet captains. Almost all of it transfers over to non-aviation analysis.
Edit 6/26/20 to correct typos.