Sometimes the first 3 minion spawns will spit out 1 or 2 items per spawn. Or nothing at all because that make sense, right? Sometimes players won't necessarily hold on to them on the sideline and just throw them onto the champs they have on the field to get that moderate advantage over someone who has 1 item or none at all. You could end up fighting someone in the first PVP round with 1 to 3 full items.
This move is similar to people rushing their levels to get 4 champs before the first PVP fight or 5 for the second, usually two of the same champ.
The difference between these two things is that one is completely RNG and unfair while the other is arguably nothing more than a tactical decision.