No rules are broken as long as they are not diving under BSAC auspices. Those customers are given the option to join PADI-run Chapters, which gives them a chance to interact and gives PADI future sales opportunities. They like to feel part of a bigger organisation, though few are passionate enough about it to use their vote in club elections. But there are still many independent diving clubs that feel no need for affiliations, and save the expense. Like me and my friends in Majorca, they just get together to go diving.
Most people still start by wanting to learn to dive.
They know training is necessary and they want a certificate everyone will recognise. But it is the diving that comes first. The rest is mere distraction.