Sheds then there are sheds. Once it becomes a place of education, then the regulations are there to protect public safety: access/egress , disabled access, fire safety, health and amenity all tend to become greater than structural issues for small buildings: for which the structure has probably been pre-engineered. Which tends to lead to people not disclosing what they actually using a shed for: not a sensible thing to do.
By passing building regulations not a good idea likely to get caught eventually. Large part of the work we do is assessing illegal construction: life would be a lot easier if it was at least documented, photographed and measured during construction, along with all invoices and receipts clearly identifying materials used. If cannot be assessed then cannot be approved, and therefore has to be removed.
Having removed probably a lot more expensive than getting designed and approved in the first place.