If you want to really do a good experiment here: go to an oil change place and say "Please drain and refill with Mobil One Synthetic 0W-40 (and filter replaceme

If you want to really do a good experiment here: go to an oil change place and say "Please drain and refill with Mobil One Synthetic 0W-40 (and filter replacement per spec for your car, specified explicitly and technically), and please put a sample of waste into this Blackstone sample bottle. Thanks.!" I'm pretty sure technical competence trumps gender. Not that you shouldn't still get treated well without flaunting knowledge, but it seems like a good way to mitigate this fairly pervasive tendency. I see this at gun stores all the time; woman goes in and is treated as unfortunately expected; reveals that she's a manufacturing FFL and knows the intricacies of both use-of-firearms and various forms of metal treatment in manufacturing, and is treated like an expert.