There is no warning because there is a bug 47848. I am not sure how big the /boot filesystem needs to be, if it doesn't tell you (or it doesn't warn you that it is too small), then it seems to me that you should open a new bug report. I am not sure how big it should be. Ext2 or Ext3 are good filesystems for /boot. Backup your data anyway. :)
@khurram
There is no warning because there is a bug 47848. I am not sure how big the /boot filesystem needs to be, if it doesn't tell you (or it doesn't warn you that it is too small), then it seems to me that you should open a new bug report. I am not sure how big it should be. Ext2 or Ext3 are good filesystems for /boot. Backup your data anyway. :)