A union is definitely the gold-standard defense against nonsense like this. But a lot of places have significantly higher employment protections that the US.
Remember, it's not always you that has to go to court to fight an NDA clause though. If you've resigned, and the company is insisting that it can search your devices because the NDA says so, the company is the one that needs to convince a judge to grant a court order allowing it to do so. (Again: not legal advice! But my understanding is that's how most contract rights need to be enforced.)
> the company is the one that needs to convince a judge to grant a court order allowing it to do so
Except they still have the legal advantage of more moneys and lawyers. There is no easy win unless the judge intervenes before you pay lawyers too much.
You can also just string it out, and on the first day you are due in court say "ok here it is". You dont need to pay a lawyer anything, the company just has to prove that it is really committed to getting this info. To go as far as having a court date set and lawyers ready to turn up. Personally I would arrive at court to ensure they sent some actual lawyers and then if I couldn't argue my point happily hand it over at no expense to myself other than taking a day off to attend court.
True, but it still puts the work of filing etc. on them. You can always self-rep. It's usually not a good idea, but here your argument is really very simple: "I signed this NDA on the basis of specific assurances, which were false. I have a record of those assurances from [company lawyer]."
Remember, it's not always you that has to go to court to fight an NDA clause though. If you've resigned, and the company is insisting that it can search your devices because the NDA says so, the company is the one that needs to convince a judge to grant a court order allowing it to do so. (Again: not legal advice! But my understanding is that's how most contract rights need to be enforced.)