Você pode dar uma olhada na página do manual e no link link
$ apropos CRDA
crda (8) - send to the kernel a wireless regulatory domain for a given ISO / IEC 3166 alpha2
saída do homem crda:
CRDA(8) Linux CRDA(8)
NAME
crda - send to the kernel a wireless regulatory domain for a given ISO / IEC 3166 alpha2
SYNOPSIS
crda
Description
crda is the Linux wireless central regulatory domain agent. crda is intended to be used by udev scripts and should not be run manually unless
debugging udev scripts. crda is triggered to run by the kernel by sending a udev event upon a new regulatory domain change. Regulatory domain
changes are triggered by the wireless kernel subsystem (upon initialization and on reception of country IEs), wireless drivers, or userspace
(see iw ). Upon a regulatory domain change the kernel sends a udev change event for the regulatory platform. The kernel ignores regulatory
domains sent to it if it does not expect them. The regulatory domain is read by crda from the regulatory.bin file.
RSA Digital Signature
If built with openssl or gcrypt support crda will have embedded into it an RSA digital signature which will prevent it from reading corrupted or
non-authored regulatory.bin files. Authorship is respected by the RSA public key packed into crda. This specific crda package has been built
with an RSA public key from John Linville (the Linux wireless kernel maintainer) and as such will only read regulatory.bin files signed by him.
For further information see the regulatory.bin man page.
UDEV RULE
A udev regulatory rule must be put in place in order to receive and parse udev events from the kernel in order to get udev to call crda with the
passed ISO / IEC 3166 alpha2 country code. An example udev rule which can be used (usually in /lib/udev/rules.d/85-regulatory.rules ):
KERNEL=="regulatory*", ACTION=="change", SUBSYSTEM=="platform", RUN+="/sbin/crda"
Environment variable
Set the COUNTRY environment variable with a specific ISO / IEC 3166 alpha2 country code and then run crda without arguments. This will send a
regulatory domain for that alpha2 to the kernel.
SEE ALSO
iw(8) regulatory.bin(5)
http://wireless.kernel.org/en/developers/Regulatory/
Para responder ao resto da sua pergunta: não, isso não é uma coisa ruim. O domínio CRDA (não semelhante ao CDRA no assunto) é relevante para a escolha dos canais sem fio permitidos para um determinado país. Nem todos os canais são permitidos em todos os países.
Exemplo: para a Europa, temos os canais 12 e 13, que não são permitidos na América do Norte.
Veja também link