But these are the rules right now, whether or not it’s in Taiwan’s interest is a political debate, we don’t want to see OP receive permanent consequences for the rest of their life.
It doesn’t alienate future tourism. The amount of time given is already in line with what tourism is. 90 days is perfectly fine for the vast majority of tourist trips. The line has to be drawn somewhere.
I certainly agree that OP should not be cavalier, or disdainful towards the law. I wasn’t really bringing politics into it. More that, if there’s a legal grey area, an enlightened civil service might lean towards leniency, if OP is respectful, proactive, and acts in good faith.
I may be wrong, but if you go through immigration on the 5th - that would be the date for the exit stamp?
I seem to recall having a similar experience?
What date did you arrive in Taiwan? If you had plans that meant an overstay it’s odd that you would have been allowed board your flight to here and be cleared by immigration.
The safe move is to change the flight. Second best is go to immigration. Third would be get to the airport good and early, make sure you get through immigration while still legal
Anyone can change a flight booking but sometimes there are additional costs involved.
Changing flights seems to be the safe option to me. Option 2 is worth a try if OP doesn’t want to change the flight. Option 3 doesn’t work - boarding passes are usually issued a few hours before the flight departure time. It would be tricky to get to passport control without a boarding ticket…maybe online check in but if OP has any luggage he is toast.
It’s tricky, but doable. I’ve had boarding passes issued earlier，for reasons. And anyways a few hours is all they seem to need…
Go to the NIA with your fight tickets and itinerary and explain that you might be overstaying a day with your current schedule and it might be difficult to reschedule a flight out of Taiwan plus with a typhoon looming around Taiwan at the moment, they will consider extending your visa by a week. I’ve done this before when my parents visa were expiring a day before their scheduled flight out of Taiwan. Good luck! 
Has that happened with the new rules? They are not as understanding about it as before.
It is also different if you are a parent of a citizen and… that visa is an extendable one.
Not sure what the new rules are right now, but it was during pre-covid when we got the extension.
I’m not sure if it was due to the fact that I was a citizen that they decided to give us an extension (they never checked our ID’s or even asked about our residential status)… and both our parents had already extended their 3mth visa once to 6mths, so their visas were non-extendible.
The extension they got was an emergency extension, it’s basically a very small blue stamp they put right on top of the original visa stamp with the last date of stay written by hand. I believe this kind of extension is granted pretty much upon the discretion of the NIA officer. So it’s best the OP @roshna get all her docs ready before going to the NIA to plead her case. If NIA rejects it, then you will need to go to BOCA. Do all this before your visa expires. Do NOT intentionally overstay.
Post COVID everything has changed. New rules are posted.
It is the 6th.
What was the outcome?