Advice needed for Prospective Student Visa

Does anyone have any experience applying for this visa?

Basically, I'm helping my girlfriend apply for this visa to come over and visit various UK language schools before committing to study at one of them and then switching over to the Tier 4 Student visa - switching over is allowed on this visa.

Now, the prospective student visa falls under the "special visitor" category and so it allows financial sponsorship by individuals. This is unlike the General Student Tier 4 visa where the funds have to be in the name of the student him/herself.

With this in mind, I'm going to sponsor my girlfriend to come over. But what worries me is that when assessing my girlfriend's application, they will say something like:

"Although with your sponsor, you have enough funds to maintain yourself and study for 6 months, you do not have enough funds in your bank account alone and thus would not meet the maintenance funds requirement for the Tier 4 visa. For this reason you have been refused"

Does anyone know if a rejection on these grounds could happen? I mean, if we meet all the requirements for the "Prospective Student Visa" which allows an individual financial sponsor, can we really be rejected because of not meeting the requirements for the Tier 4 visa?