“Surely it is necessary to coerce children to avoid them doing unsafe or unethical things?”
Children do not want to do unsafe or unethical things any more than we do, so no, no more than it would be necessary in your own case. (Having said that, see this slight caveat about the importance of intervening to protect the victim if one child is physically attacking another, and this post about how to intervene non-coercively.)
It might be that they want to do something that they themselves do not think is unsafe, and that we do think is unsafe, in which case we let them know why we think it is unsafe, so that they can make an informed decision. But often, things we parents think are unsafe aren’t. I think sometimes we assume that our children are less able than they are. Young children are often superb climbers, for example, and yet, when we stand ready to catch them if they fall (as seems like a good idea!), they do not actually fall. (Note that if, while you stand ready to catch them if they fall, you are exuding worry, disapproval, or if you feel sure the child will indeed fall, you yourself are likely to cause that very outcome.)
And the old chestnut about children drinking bleach is clearly rubbish given how unpleasant bleach smells. (Not that it is a good idea to leave bleach lying about for a young child to happen upon when you are out of the room, obviously.) If, on the other hand, we happen to have a highly toxic sweet-smelling substance lying about (like the highly carcinogenic transparent orange benzene-related liquid I myself had a massive exposure to in Chemistry A Level class in school), there might be a risk a young child might drink it, so definitely do not have such hazards in your house.
I would, though, if you think your children might be interested, show them the bleach, and show them what it does, and how to handle it very carefully. It is far safer to show children potential dangers and how to handle them safely, than it is simply to rely on them never interacting with such dangers. (I am definitely not including things like benzene in this, unless you have a professional laboratory setup in which you can handle the benzene without breathing it in – it is a known cause of myeloma.)
Even if you yourself keep all the dangerous items and chemicals locked up, there will come a day when your child is somewhere else, where that is not the case, and then your child is potentially navigating dangerous things with no knowledge of how to do so safely. Taking our children seriously is so much safer than the alternative.
Is coercion always wrong?
How do you intervene non-coercively when one child is attacking another?
Do Explain podcast with Christofer Lövgren #16: Taking Children Seriously, with Sarah Fitz-Claridge
Sarah Fitz-Claridge, Taking Children Seriously FAQ: ‘Surely it is necessary to coerce children to avoid them doing unsafe or unethical things?’, https://www.takingchildrenseriously.com/surely-it-is-necessary-to-coerce-children-to-avoid-them-doing-unsafe-or-unethical-things/