Ran into something yesterday that made me pause and think.-- Got a call from a customer that lost half the electric in their house. Turned out to be a bad 200Amp Main - Unfortunately it was a Pushmatic panel. After replacing the panel we went through testing out the house- just routine to make sure everything is working ok. Discovered that several circuits in the remodeled basement all had the polarity reversed.- I brought it to the attention of the homeowner. I told her it was not right and should be addressed. She asked me if it was dangerous because it had been that way for years.- I was a little unsure what to tell her.-- Yes it could be dangerous for anyone working on the system but beyond that not sure what the danger would be.
Afterwards I thought about several other dangers- light socket shells being energized certain equipment or appliances being damaged or worse having cases energized etc.
So my question- what all dangers are inherent in a reversed polarity circuit? Should I have been more forceful in encouraging the customer to get this fixed immediately?

IMHO, you covered most of the bases on reverse polarity. One question, when doing the panel swap, did you notice anything?

As for myself, I could never walk away from a reversed polarity situation.

If the neutrals were correctly landed at the panel...

I'd identify the offending circuits PDQ and untangle them.

A hand full of circuits sounds like short work.

thanks for the feedback- no I did not notice anything out of the ordinary in the panel. Yes all neutrals were landed properly in the swap. The issue is defintely in the wiring. I actually took one receptacle apart- black and white clearly reversed on the receptacle. I assume that is the case on all the other circuits I tested out as well.
- I think in hindsight I should have been more forceful- I quess I was just feeling bad for them - they already were looking a significant- unexpected bill- for the panel swap, I didn't want to rub salt in an open wound so to speak.

One other thing- fixing the problem would not be short work. If for not other reason than finding all the offending receptacles would involve moving a LOT of furniture and junk. Probably a solid days worth of work.

I've seen reversed polarity that changing the polarity resulted in switched neutrals. Then, you have to decide whether reverse polarity is worse than a switched neutral. It's the sort of thing that you never know about in advance. If the customer won't (or can't) pay for the repair, you can't do it for free. I like the drive thru oil change solution. Tell the customer and note it on their invoice. You have to trust that they will promptly have it fixed.