People know that final grades are being averaged, that coursework is being taken into consideration and that final exams are open book and allowed 24-48 hours to complete
These things are standard in my discipline, both at my place and nationally (I know this because I chair a national teaching organisation in my field).
Degrees in most if not all English, Welsh & NI universities have always been based on various arithmetic calculations of all marks achieved in 2nd and 3rd year (Scotland has a different system). Different universities have different systems for acknowledging what we call "exit velocity" - that is, ensuring that the fact that - generally - most students know more and thus perform better in their final year, than previous years.
Open book & take home exams are a regular and legitimate pedagogical tool, particularly in essay-based exams. If a student hasn't assimilated and processed knowledge and thought about it in complex ways, they won't do very well in an open book or 24 hour exam.
Actually, pedagogically, it can be argued (some education experts do) that a 24 or 48 hour open book exam (a 'take home exam' we called them when I worked in Australia and the USA) is a far better indication of a student's real, processed, and permanent learning, than an exam crammed for, and blurted out onto the page in 3 hours.
Open book/24 hour exams can better replicate conditions in modern workplaces. I can remember my A Level Chemistry teacher encouraging us to check our knowledge in lab reference books, rather than rely on our wonky ability to memorise the periodical table of elements, for example. For our exams, we had to memorise it, but he told us that standard lab practice was always to check.
Or I sometimes in the academic workplace, get a long document plonked on my desk/computer screen, and I need to read it and produce a precis for colleagues, or develop a policy recommendation etc etc. Pretty much an open book exam, drawing on my deep background processed knowledge of a field.
And so on.