Sorry for late response. Currently driving across Europe back to the UK!
Unfortunately, if any applicant received an email from a uni congratulating them on their place the night before results, or anytime before 08:00 on results day, then they shouldn't have done! That's breaching the results embargo for A level results. This may not apply if the applicant took the IB or other international quals, but good practice is not to communicate anything at all until after the embargo ends.
It is quite common, however, for applicants to find that they've got a place on the morning of results day. For example, they could check UCAS Track at 08:01am and see that they're 'unconditional firm' at one of their choices, even though schools might not open until later for collection of results.
@stilldumdedumming - about clearing grades: very much depends on the policies of individual universities. I guess some might accept lower grades than advertised for courses in Clearing. If an individual has a strong application (as I mentioned in a previous post, above) with content relevant to the course in question, then that would put them in a strong position. You can but ask, and we can only say no!
We know how stressful this time is to our applicants. We always try and make it all run as smooth possible. I remind my team that we're dealing with young people at an important point in their lives, and not just a clutch of UCAS numbers. Rejecting people is hard, but hearing relief in voices when you make them a verbal offer during Clearing is just amazing!