IN NH You can use a crossbow during the firearms season if you want to use a crossbow during archery you have to get a Disabled crossbow permit (all you needed was a doctors note) SO I assume it was being abused looks like it is only for one year you can go back to a bow the next year
Here is the crossbow rule section taken from the book
Crossbows
Annual Deer Crossbow Permit
(annual;
$5) allows the hunter to use a crossbow
during the firearms deer season only. The
hunter must have a valid firearms deer tag
and follow all Wildlife Management Unit
restrictions for deer during the firearms deer
season. Any deer taken shall be tagged with
a valid firearms deer tag.
Disabled Hunters
Disabled Crossbow Permit
(permanent;
$10) allows the use of crossbows during
any season where use of a bow and arrow
is allowed. This permit must be applied for
at Concord Headquarters. A current year
hunting license is required. This permit
does not include separate tags (all ages).
New for 2012, hunters holding a disabled
crossbow permit will be limited to using
only a crossbow. They are not allowed to
use a longbow, recurve or compound bow.