The banner is default for everyone atm (I guess). Because my account is trusted, so are the accounts for several other people I play with and we could use the features of the trusted account.
But we all got the banner 
Problem with trusted status itself is, that no one really seems to know what all counts to it. According to what we currently know and what AGS said, they only get the info from Steam if an account is trusted or not. Now Steam on the other hand seems to use several possible factors.
You can raed more about it for example in the CS Community of Steam:
Steam Community :: Guide :: The Trust factor
(you can find several other sites with discussion about the trusted status, all basically listing the same factors. Some sites even claim that you can check your trust status by giving them your Steam ID, but I wouldn’t recommend doing that)
From my personal experience within my LA guild the following seems also to be true:
- if you have bought something in LA but don’t use Steam Guard App, you are still trusted
- if you have Steam 2FA via mail(!) but didn’t by anything from LA and don’t use Steam Guard App > you might not be trusted
This was just an observation based on what happened to 2 people in my guild.
Person 1: bought a skin back in April but doesn’t have Steam Guard App > still could send ingame mail with items to guildmates
Person 2: never bought anything in LA but has 2FA for Steam via mail > couldn’t send ingame mail with items anymore since 2 days > this person activated Steam Guard and it took ~1h and he could send ingame mail again
And always keep in mind what AGS said: they are rolling out the feature and testing it currently!
So it might be the case that only a few accounts are verified in regards to this trust status atm and it might also be the case, that the feature itself has some issues, which can (hopefully) only be solved if someone has problems and contacts at least AGS support and also Steam support.
And also have a look what AGS/SG said when they introduced the trusted status back in the first place:
Players who have a Steam account in good standing and have met the small purchase requirement needed to use Steam’s social systems shouldn’t be impacted. Players who have not met this ‘Trusted’ status through Steam or Lost Ark
Important point here being “Steam OR LostArk”. So there are to trust systems in place! And like I described before and which also fits my speculations: if you bought something from LA shop, you are trusted from the view of LA. If you have activated Steam Guard App but never bought anything in LA store, you are also trusted. 2 systems, same effect. (but this is just my speculation/observation)
Source: March 24 Weekly Update - News | Lost Ark - Free to Play MMO Action RPG (playlostark.com)
Personally I find that the communication of AGS again was not ideal (again…), it almost certainly want to anything against most of the bots/gold sellers and it is especially bad that the status of being trusted or not is handled very intransparent (as you can see from the CS community, people keep on speculating about this since 2017), which is mainly a problem of Steam and exists for several years know.