Yes it is difficult to take into account any sort of label on the outside of a plastic seal, but we strive to have this correct information. Even to that point that we would prefer an image of something sealed, if in sealed form there is some label that would otherwise not be seen or known on a loose or secondhand copy. And in an case like this, it would be put into Description field that there is a label on the outside.
See this entry for example:
https://vgcollect.com/item/9622As for the EU game with Italy flag and/or Italian language, but not the SIAE label (sealed or otherwise) I have a suspicion that these games were not actually sold in Italy. However, not being from Europe, I often would defer such determinations to people who live in those countries. Only from my own research, I know that the SIAE label should be on the
outside of all media or products containing media sold
in Italy.
This means:
1. Games that are pack-in items with accessories or consoles can be legitimate Italy releases despite having no label, as the required label would have been present on the outer packaging.
2. Games with Italian text/flag on them may have been intended for sale in European countries where Italian is a spoken language but is not covered by the SIAE requirement.
I have a good feedling that #2 is correct, but I do not know enough about where those types of places may be. I know that this is why there are French games without the Attention box, as there are other countries that speak French but are not in France and thus are not required to put that Attention box onto retail packaging.
For verification purposes, I typically will look at the regional Ebay. For Italy's case, it would be ebay.it using current and sold listings (completed listings is often a waste of time). If there was a thing that I knew to exist in a certain country, but not able to be found on Ebay, then I would investigate other online sale/auction/classified sites for that country. Currently I do not know any for Italy. But usually Ebay is good enough to figure things out without having to visit many other websites.
