[hunter2_]

As a guy who gets attempts at being ripped off by mechanics (unnecessary work coming very highly recommended), my solution was not to somehow introduce more masculinity, but to educate myself by hanging out on forums specific to whatever car I'm driving, and mix a bit of that education into the conversation with the shop, bordering on what could come across as knowledge bragging. For example, while waiting for work to finish, I'll watch a video on something it ostensibly needs and then bring up the fact that I did and might DIY it. Typically the service writer will then be on my side instead of seeing me as a money tree, and the frequency of ridiculous recommended work after that drops to almost nothing. Ymmv and indeed people will write posts on those forums with male salutations for no apparent reason, but otherwise that's where I found the truth.

[pwinnski]

Which is great! You only had to exert a bunch of extra effort, and it sounds like you've enjoyed the results.

Now read some stories from women who've also made that extra effort and then some, having more experience and knowledge than the mechanics trying to rip them off, and still being given the runaround more often than not.

A shady mechanic will be shady to some degree to everyone to the degree they think they can get away with it. No amount of self-education on the part of women lets them escape the shadiness.