All the best to your applications,
PianoSecrets-x. Although I can't help much, not having studied in the UK, I think Czerny was just trying to advise that your choices should be wisely used.
As you were probably really exhausted from dealing with all the application procedures, you did sound (in your first post) as if you were just trying your luck with one of the top schools, just to prove your ability, even though the intention to actually accept the offer in the case of a successful application is not strong. Perhaps you should reconsider your strategy and place colleges that you are interested in first.
Not very sure how the admission/selection process is like in the UK. Have you found out how the selection works? In my country, the order of choices are extremely important. Let me illustrate why:
If the following is the order of your choices:
1) College A
2) College B
3) College C
, your application will reach College A in the first round. If you aren't successful (e.g. College A being very competitive), your application will then be routed to College B for a second round of admissions. By the time College B receives your application, it has already admitted those who placed B as the first choice in the very first round. As a result, there will be fewer places left for the course you applied for, causing a lower probability of admission for you.
If your favourite option were College B, would it not be a real pity that you did not place it as the first choice? You could have easily gotten into B if your application was received in the first round.
Just my two cents' worth. Perhaps the UK admission procedures aren't the same.

No matter what, don't forget that you will be the one studying, so your own preferences should be seriously considered. So, no hard feelings against Czerny or anyone else who advises against applying for Cambridge, OK? Good luck!