well...
some of these extra channels (although illegal)
are used for international contacts
such as 27,555
basiclly the 40 channels of CB / 11 meters is
26,965 to 27,405
although it is illegal to use CB above or below those frequencys
just like 11 meters is limited to using 4 watts am and 12 pep SSB
so is it illegal to go above or below "regular" 11 meter channels
However
if one is into SSB and into skip
then you will (especially when skip is good)
find people going as high as 27,695 (i would not go higher to be sure you do not slash over onto the 10 meter frequencys.. where if you did it may turn out some ham op will have you reported..
you may want to go lower then 26,965 if you like AM skip
i have found 26,815 and 26,915 are good for that
Whether you chose to do so or not
just be carefull and be reasonable in how you use it
you expose yourself to higher risk
for sure you do not want FCC to come a knocking with those nice fines they like to give and to take your gear
myself
i can care less if one choses to use what is refered to as the freeband
just know what you are getting yourself into
besides that
Enjoy