Which region/country are you referring to? What's the use case?<p>IANAL, but I used to work at one of the large transportation providers. For the high-volume tracking use cases, web site scraping probably won't cut it (too slow, probably get blocked by the carrier). Most high-volume trackers used the carriers' APIs. It was sort of a love-hate relationship and my carrier would sometimes block high-volume carriers who ran refund services on behalf of other customers.<p>In short, whether it's "legal" or not, if you are doing a high volume of tracking for refunds you will be at the mercy of the carrier who could cut you off at anytime. A firewall against that is to have a bunch of high-volume paying customers of that carrier who would pitch a fit if your service was turned off.<p>[Edited for clarification]
From experience with using carriers tracking information world-wide: scraping will be fine for low volume usage and if we are talking personal use cases.<p>If this has any professional smell (as in you make money with whatever you use the data for) you will want and need access to each carriers API for several reasons:<p>- accuracy of data: this is not guaranteed for the web views, they may (and are) usually outdated by hours
- volume of updates: carrier APIs usually come with rate limitations and can also require contracts for uses