Article 422.52 and 680

[fbhwt]

As of [2011], the relevant section, IMHO, is 110.16 (emphasis mine):
Arguably, that means that the label should be visible before you open the door to examine the breakers, etc.
The section also refers the user, via an informational note, to NFPA 70E, which has additional guidelines.

Now other required panelboard markings, by contrast, are explicitly permitted to be inside the panel, just not too far inside:

Note that the 408.58 markings must be placed by the manufacturer, and so cannot be on the removable/interchangeable cover, while the arc flash labels are by their nature specific to a particular panelboard in a particular location, and cannot necessarily be supplied by the manufacturer.

To me there is no arc flash hazard with the panel cover in place, by removing the cover and dead front exposing live parts then we have a potential for arc flash, and only qualified persons should be doing this.

 

[GoldDigger]

To me there is no arc flash hazard with the panel cover in place, by removing the cover and dead front exposing live parts then we have a potential for arc flash, and only qualified persons should be doing this.

On the other hand, there are quite a few statements that simply operating a circuit breaker can generate an arc flash, which can be done with the dead front in place.
I am not arguing that there is an arc flash hazard (greater than miniscule) associated with opening the panel cover door. But the exact wording of the NEC says nothing about any specific arc flash hazard, it describes a set of interactions, which include "examining".
Now examining the state of a particular breaker after opening the door is again not an event likely to cause an arc event. Nor would it be "interacting" with the breaker in the wording of 70E. But, nevertheless it is "examining".

If the person who interprets this code section goes strictly by the language of the code rather than any reasonable justification for that language, you will lose a good percentage of the time.

 

[Smart $]

Without researching the finer points of all the requirements of various standards, all I can say is arc flash labels on the exterior surface of all personnel entries is commonplace in locations I work.