My son's U14s match I was at last week as a parent reinforced my view that referees should use cards if necessary for u13s and above, sooner if the incident is serious enough.
"Referee" was a member of the home team's coaching staff. From the very first minute, the home side appeared intent on kicking my son's team off the pitch. By my estimation, for every 10 blatantly obvious fouls they committed, the referee gave 2 or 3 fouls at most. One home player particularly had the air of playground bully. One of the few fouls that were given during the first half was for a fairly shocking "challenge", which could quite easily been a red card by said playground bully. Player responded to the foul being given by booting the ball halfway down the pitch. Referee never said a single word to the player for either the foul or the obvious dissent that followed.
A member of the home teams coaching staff took him off a few minutes later "to calm him down", but clearly didn't work as when he eventually came back on, he appeared even more wound up than when he started the match!
Another incident near the end of the 2nd half, A home team player was on the floor and being treated for an injury, not sure if words were exchanged between some of the players, but whilst players from both teams were standing around waiting, a home team player picked up the ball and dropped kicked it at an away player at close range, again the referee did nothing!
There were many other incidents where the "referee" turned a blind eye such as 10 yards at free kicks? Nah, more like 2 or 3. As well jumping in front and attempting to block the keeper's clearance from hand.
The home side was the prime example of a side that were used to having a manager/dad referee their games, probably poorly coached and never been subjected to match discipline. Sooner or later they will come across a referee that is unwilling to put up with their behaviour and be of the receiving end of many cards. No doubt when it does happen it will probably be a complete culture shock for them and prompt complaints that the "referee lost the plot".
Fortunately my son's team had the last laugh, coming out of the game without suffering any serious injuries and won the game 12-1!
Managed to keep my mouth shut on the sidelines, had I been refereeing, might have got a RSI from dishing out cards!