Repeating my post in another thread (where you asked the same):
The guarantor is only responsible for the text that they sign, which is on the passport form on the first page.
I'm going to simplify: they swear that they have known the person for at least two years; that the photo (which they also sign I think) is a true likeness; that they've looked at any supporting documents (if any); and they look at the rest of the application form and that it is true to the best of their knowledge.
I put true 'to the best of their knowledge' in italics because this is important - the guarantor is NOT expected to check or make any inquiries to confirm any of the other details on the application, they are NOT stating that everything is true. They don't have to check your work history, height, what exact date you became a citizen, they're not expected to be document experts, confirm your addresses or your family status, age, place of birth, etc. In fact the guarantor doesn't need to know ANYTHING about your immigration/citizenship status is true - just that you are, to the best of their knowledge, the person claiming to be XYZ. True 'to the best of their knowledge' means exactly that - if they think any part of it is NOT true, they can just not sign. If they don't know whether some part is true or not, that's fine, that should not prevent them from signing.
Their only 'liability' is getting in trouble for making deliberately false and misleading statements. That is, if they didn't know you at all and signed this, that's a false statement. If they didn't know you never studied at university X (as you had always told them), there's no issue.
They are NOT taking any responsibility for your behaviour, financial success or not, etc. None. Only that as far as they're aware, the info is true and they've known you a couple years.
In broader terms: as far as I'm aware, the guarantors are rarely if ever 'held liable.' The applicant takes the responsibility first and foremost. It's not worth government's time to pursue guarantors if there's some issue (amongst other thigns, hard to prove the guarantor knew something was false). I'm sure there are exceptions, but I'm quite confident they would only be for cases where guarantors had repeatedly, knowingly, purposefully, and maliciously done this - imagine somebody working in a shady 'get you a fake passport' business.
In my view no normal citizen should be remotely concerned about signing as a guarantor - as long as they know the person applying and have seen the picture. If anyone IS concerned, it's my belief they are simply scared by the word 'guarantor' - and I wish the government would change it for this reason. (It really is no different in most respects than someone witnessing a document, with the same risks of issues - very low).
They are not 'guaranteeing' anything except that they've known the actual (physical) person for at least two years. They're not legally or financially responsible for you - only that they told the truth on the docs they signed.
In the 'old days', the guarantor was one of a limited number of trusted professions - doctors, religious officiants, lawyers, certain govt officials (lots of them actually), etc; I forget whether teachers and professors were on the list. People in these professions routinely signed guarantor docs for passport purposes, as far as I'm aware for free; it was considered another small public service they were expected to provide as part of their public 'license.' Note most of these are regulated and/or given certain authorities by government; they're used to signing docs where they take personal and professional responsibility. (My father was in one of these professions and did it all the time; he was happy to do so, it was part of community service. Everyone related to his work but also our neighbours, our street, parents of our school chums, everyone - as long as he knew them two years).
People complained for various reasons, and they changed it. I think many complained they didn't know a doctor or lawyer or dentist or priest, etc. I'm sure some of these professions complained it wasn't compensated work. I'm not convinced it's made anything better to change it.
