You'll be surprised how many people will take offence or retort with 'not illegal what'. Singaporeans are used to being babied by the nanny state so they'd only take action if they have 'official' reason to back it up; we frown upon vigilantism/lack backbone. That's just our style of societal engineering - disbursements for desirable behaviour like recycling bottles and cans (even for reading books!) and fines for vices like smoking

I do it quite often but I hate that I need to do so ...

Also, I have to do a crazy assessment beforehand in case I may get stabbed or something.

Hi, I’m a disabled trans woman. If I told someone with their music out to mute it or put it in headphones, even politely, at best I would be ignored. At worst, killed. Prolly get beat up, that seems to be at the top of the curve.