[Freeswitch-users] Detecting and blocking fax calls

We receive an inordinate amount of spam fax calls to FreeSwitch that we do not need to handle for any reason. I came across this method, https://wiki.freeswitch.org/wiki/Misc._Dialplan_Tools_fax_detect, to hopefully detect and drop these calls. Is there any danger of this method mistaking any live calls and dropping those on accident or is there a better method to accomplish this? Thanks in advance.