Most of the communications lawyers are not radio geeks in the strictest sense. A few are. They mess up call letters in the US also. One common call letter mistake is that if there is a double consecutive letter in the callsign, they will double the other letter. Another common one is to substitute K and W for W and K in the callsigns, particularly if they are from the areas of the country with no mixture of callsigns. A "Philadephia Lawyer" or one from near the Mississippi River is less likely to make such a mistake.
Another common callsign mistake is call letter reversals, although lawyers are probably less likely to be dyslexic.
Even Mexico's own broadcasters can't spell their own callsigns correctly.
When they executed the AM-FM migration program, hundreds of new FMs went on air. In some cases, to avoid duplication of callsigns, not only was the XE changed to XH but an E was tacked on (for instance, XECPQ-AM became XHECPQ-FM). We have airchecks of XHECPQ identifying as XHCPQ. And they're not alone in making "AM-FM migration errors".
In 1994, when the SCT authorized FM combos to some 80 AM stations nationwide, they did not care if there were FM stations with existing "matching" calls. That's why there are two XHCHHs, two XHPRs, two XHFLs, and two of about 21 calls in total. (A 22nd conflicting pair was mitigated when the combo changed its callsign.)
Another four are duplicated for some strange reasons. There are two XHRRR-FMs, because an AM-FM migrant and a newly permitted radio station both got the callsign. There are two XHGZ-FMs for the exact same reason. A station changed its calls to XHCHI-FM in 2003, meaning it now shares those calls with a flea-powered public radio repeater in another state. In a truly special case, XEA-AM and XEAC-AM migrated to FM and *both* got the XHAC-FM callsign. (At one time the two even had the same national syndicated format!)
There are also some amusing cases of callsign misspellings being enshrined in concessions and permits. The most accessible is XHEUH-FM, which serves T
ehuacán, Puebla. I believe the intended callsign was, uh, XHEHU-FM.
As to the lawyers' mistake, there actually was a KXED, which broadcast on 1540 in Los Angeles in Spanish, from 1992-96. Tucson has had—for decades—a KXEW, which is indeed named for the Mexico City station. There's also a KXEQ in Reno, which broadcasts in Spanish.