I'm applying for a programmer's job in Taiwan at a new startup (with foreign investment) that doesn't yet have a website. The first stage of the hiring process consists of completing a simple pilot project and sending in the undergraduate transcript.
In the past, I have had HR ask me to write down the contact information of any one manager and one co-worker who knew my work ethics before the interview began. At the time, I was inexperienced and eager to switch jobs, so I gave them, a competitor of the company I was working for (there was no non-compete agreement), the information without getting the consent of those two first, and without regard to the possibility that they might use it for staff poaching.
Another story involved the HR at a different company requesting me to fill out the new hire employee information, which had a required field asking for my parent's national identification number. I was uneasy with this and inquired the HR why they needed it and if it was mandatory. The reply was that the form hadn't been updated for a long time and that column was just a formality and not a requirement.
There seems to be a tendency among employers to ask for more information than necessary from their employees/candidates, and few even had a policy detailing how they use and retain that data. Hence this question.
How can I push back on a prospective employer's request for sensitive information during the pre-employment process, that I might be willing to give them if I were to accept an offer of employment, in a way that offers me the best chance to still get that potential offer?
P.S. It would be nice to also have answers that detail the need for sensitive information (e.g. national ID number for tax filing purpose, upon hire) so I know where the employers are coming from when they make those requests, that they're not just a "formality".