It's understood that Papali'i was breath tested at a compulsory stop when he was shifting his car between paddocks at the festival.
"It's a really good lesson for him but you have got to put it in context," said Kearney.
"Trust me, when you are wrong you're wrong, but in terms of the details of it … it was on the minor side. I'm not going to go into the details of it but it was the next morning and it was minor … but that's the lesson for him. You just can't do it."
Kearney admitted he was disappointed, but said there wouldn't be any further sanctions put in place by the club.
"He's not available this week and it is as simple as that," said Kearney. "I don't know all the details but drink driving is drink driving. It's a big mistake by him but I know he is a decent kid. But's a wonderful lesson for everyone."
It's a significant blow for Papali'i, but also the team.
The former Richmond Rovers junior was immense last season, and one of the most improved players across the NRL. He played 20 games — after only featuring once in 2017 — and was a revelation with his uncompromising defence and non-stop work rate and regularly belied his inexperience with mature performances.
One of the strongest players in the squad, Papali'i also developed the attacking side of his game over the season, with some important offloads.
Papali'i's form was rewarded with a Kiwis call up at the end of this year, and he made his test debut off the bench in the 34-0 third test win. That match was a dead rubber, but Papali'i certainly didn't look out of place on such a stage.
It was expected that he would take Simon Mannering's place in the squad at lock this year, but Australian Lachlan Burr is now likely to wear the No 13 jersey on Saturday.
The Warriors team for round one will be revealed at 5pm.
