possible evil box glitch?

Look, I know this "theory" is very easy to believe, but there's something you have to understand here.

If we were to say you can get AT MOST 5 (or any specific number) of "premium" items from the box per any specific time period, it would have to work this way:

1) Open box
2) Get good item
3) Some sort of counter is updated in the database specific to your character.
4) On the next box opened, the counter is checked from the database, and based on it (<5 or >5), you get your reward.

For Nexon to have actually implemented a script like this is extremely unlikely. It means adding a database entry for every account which will contain the number of "premium" items received, and that entry would have to be reset daily.

If you have no programming knowledge, you're probably thinking "that seems easy. it can't be that hard". It's not about easiness - it's about likelihood based on what Nexon's done in the past and the amount of effort they're likely to invest for such a trivial event like this.

Nexon doesn't go messing around in the database just to add junk info like that. That's my 2cents.

If you want to actually prove that Nexon does implement this method (once again, soooo unlikely), you'll need to conduct a trial on a much larger scale (think 1000 boxes in a day), and prove that you did not get a single premium item after you had 5.

Moreover, keep in mind that the feedback in this thread is solicited with a bias (considering the title). Those who got good items after their first 5 are unlikely to respond. Finally, I cannot say this for certain, but I recall getting more than 5 "premium" items in a day, and they weren't all within the first 20-30 boxes.

copypasta from jms, they may not even know they did it

sounds plausible.