I think it is rather rude and a bit dishonest for people to not divulge their total fees upfront, an of course we should know to ask. But the normal person wouldn't know the questions to ask until they are burnt once like this, and then there still could be costs for walking up stairs or charge another service call if they need to go somewhere to use the bathroom and come back. THAT ISN'T A QUESTION I WOULD THINK TO ASK.
"We have found our plumber for life! Jim is awesome! We just bought a house with a leak in the foundation, and in spite of the complicated and extensive nature of the repairs needed, Jim quoted us an incredibly reasonable price. Having just closed on a house, though, we were extremely short on funds, and so to help us out, Jim did a temporary fix for much less, and even though he was going above and beyond and doing this extra work for us, he said he'd even deduct the cost of that repair from the total of the final, permanent repair, when we had that done!! I can't say enough good things about him - there's much more, but I don't have room!"
Plumbers in Australia have licensing requirements that differ from state to state but it is generally accepted a 4-year apprenticeship with a further minimum experience of 2 years (6 years total) and a further curricular requirement as a benchmark for licensing. Licensed plumbers are also expected to maintain minimum relevant training requirements to maintain their plumbing license