Well .....
Every races that know something about technomage know that they do not have to be in the way.....
So they do not need to provide an ID to anyone, because no one will ask them for.
Hint : In the serie, at S1 I think, B5 security ask them for an ID ..... can't remember how it was solved .......
However, even if they have to provide an ID, it's a false one that will be given ..... a false one, but valid. (A computer hack is trivial for them, you make a false ID and you make a false record with a false bio on the main servers).
Remember one thing :
Their ID and their organisation MUST be kept secret : wherever whenever whoever.
From 2260 to at least 2268 Technomages must be hiding and contact no one outside from their guild. If a contact is made, it's with approval. If not, the technomage can have terrible penalty. Galen, for contacting sheridan and durena has been banished.
Hope that will help
P.S. : don't forget the B5 spirit .... Galen has been banished officialy ..... that may be a method to preserve galen to be exposed to several questions .... or to be captured for giving information about technomages retreat ..... witch is, for the actual technomages, the must important thing to be kept secret. ..... Another banished technomage said that the technomages were still talking to him