A complaint that I am more likely to have is where you take the work to a dealer because it requires a level of skill above a mere DIY monkey like myself.
So you take it to the expert who them attacks it like a teenager and breaks it, then charges you top rates for the priveledge!!
If it comes back in a worse state and you are still charged then I can see that you might be upset. But this was clearly not the case for the OP.
But your example prompts another question - should they charge for just looking at something. For instance, if my sus fork stopped working and the shop said that they'd have to spend an hour stripping it down to see what was wrong with it before giving me a quote for a new part do you think that they would be justified for charging for the time spent stripping it, especially if I then decided not to lash out on the new part and just took the bits of my fork home? It's meant that their mechanic has been away from other money earning work for an hour, but I haven't gotten my fork fixed.