This makes me miss 2019, when Taiwan Mobile first started offering roaming on prepaid and mainland China was only 600NTD for unlimited data for a week. I just started doing that for reliability reasons. Then they probably had too many people like me and they now throttle after 5GB. EDIT: They did cut the price to 350NTD, though, so it's not as egregious as if they were trying to sell 5GB for 600NTD.