Nothing crazy about that idea. It would depend on whether the bulbs had already emerged and, if they had, on how high they were up and the height of the cut. You can also cut the whole area down after the bulb foliage has yellowed. And I see no reason to wait until the ground has frozen. What's the thinking behind that idea? Over here people often mow or strim over where bulbs are grown in rough grass areas. And the ground barely ever freezes.

The idea is to do it before the bulbs emerge. This is a neglected area that needs more then a lawn mower...we aren't just talking grass, we are talking brush. The idea behind doing it after the the ground freezes is:

1.) Frozen ground is less likely to be compacted and squish bulbs when heavy machinery rolls over it.

2.)You know the bulbs will be fully dormant.

3.) People tend to think about gardening tasks in the warm weather...Spring and summer get "overbooked". Anything you can do in the dead of winter should be done then...there just isn't enough time in the Spring to do all the tasks that have to be done in the Spring.

Exactly what kind of brush hog are you thinking about? If it's a walk behind type rather than tractor pulled bulbs will not care whether it is a brush hog or a mower. ( I Googled brush hog since it is not a thing over here.) I am pretty sure this job could be done at any time that the bulbs are still under the ground. As I said, the ground almost never freezes here and people work over the top of bulbs plantings with no problems.