I am not saying it will get stuck but there is a chance it can get stuck on startup, there is a risk.
It is not only the capacity of the card that is risky it is more the combination class/…GB.
Just use a class 4 card off any capacity (up to 32GB) and you should be safe.
Here’s what the Sandisk helpdesk (Netherlands) has to say about card issues:
It is recommended to use only ordinary standard microSD / SDHC (class 4) cards.
It is not recommended to use. Class 6 or class 10 cards. This probably will not function and we can not guarantee that this will work without problems.
It is also for the use of ordinary MP3 files recommended to use up to 16GB cards, Supporting external cards up to 32GB microSD cards is intended for FLAC or WAV files, of course these are considerably greater than MP3.
If you consider that the best quality MP3 320kb / s, please understand that a class 4 card (4MB / s) is more than enough.
Now if they know that there might be poblems with class 6 or higher cards, why don’t they warn people not to use these cards in the zip, that’s what i don’t understand.
(Translated from Dutch)