We never see them but I get a sense that Laertes has some good friends.
Polonius suggests that Reynaldo claim connections to them (and himself) to gain some legitimacy and later, Laertes almost stages a successful coup. He must have a lot of friends and supportive ones at that.
Or if there aren’t a LOT of them, they’re very loyal. So loyal that they’d stage a coup for him. The fewer of them there are, the more loyal they must be.
They may be a little riotous but they seem to have Laertes’ back.
I’m not sure what trouble Polonius thinks his son is getting into – if he’s thinking drinking, swearing, quarreling, gaming or drabbing isn’t going too far to dishonor him. Or maybe he’s looking for evidence of those very things?
I picture Laertes a little bit like a frat boy, surrounded by a tight knit group of drinking buddies who get up to mischief wherever they go but will band together the instant anything gets serious.