As for unschooling extending to other areas of life such as bedtimes (as mentioned by the OP), the thinking behind that is that children are given as much freedom to make their own choices as is safe to do so, and that they will learn from them.
If you tell your child 'time to go to bed, else you'll be tired in the morning', they often don't believe you, or don't care, or just genuinely aren't tired yet, and bedtime is often a battle. If a child has the freedom to make the choice to stay up late, and realises that yes, they were tired in the morning, they'll learn to better listen to their own body and will naturally choose to go to bed when they're tired. Because staying up late isn't forbidden, it isn't seen as exciting and there's no reason to 'rebel' by doing so.
The same with food - if certain foods (sweets, 'junk') aren't forbidden or restricted, then they don't become exciting or desirable, and so children don't feel the need to binge on them, rather they view sweets the same way as any other food, and learn to naturally regulate themselves and listen to their body. The same with watching tv or anything else.
Some parents worry that by letting go of restrictions, children will make 'bad' choices, but no unschooled child has ever eaten nothing but sweets or done nothing but watch tv for 6 months straight. Yes, a child who was used to having restrictions may initially binge on sweets or tv or late bedtimes if those restrictions are removed, but once they realise that tv/sweets/bed will always be there, that they aren't going to be taken away again, they will naturally fall into a pattern of listening to their own body, and by doing so, they are better able to trust themselves and to make good decisions, and that means higher self esteem.
Unschooling isn't about letting children do whatever they like and sod everyone else, or letting them treat others badly or do things which're unsafe. It's about mutual respect and helping children to feel valued within a family, treated as equals. It's not about never saying no, but about saying yes a bit more.