I believe what they're trying to tell you is that the scanners sold here in the U.S. cannot be easily modified, either by software, firmware, etc., to monitor cell phones. The ECPA (electronics communications privacy act) of 1986 made it illegal to monitor cell phones and, beginning in the early 90's, scanners had to be type accepted by the F.C.C. before they could be sold in this country. It's suppose to be illegal for a person to buy one in another country and "import" it into the country but people still do. If you ever see an advertisement for a new type of receiver being sold in this country you'll see, in small print, that it's awaiting F.C.C. approval for type acceptance, especially if it receives 800mhz.
In addition to that the modualtion type used by cell phones is different than that used by public safety agencies..... no need to design the receiver to listen to something that you're not suppose to listen to in the first place, right? Besides, if you really want to listen to someones cell call all you have to do is sit next to a person in a coffee shop, they're more than happy to share their conversation with you by talking too loud.
I find listening to the conversation of a soccer mom talk to the rugrats rather boring......