Yellow cards are not encouraged at Mini level, rather a word to coaches to ask for the player to be subbed.
However, Red cards are a different matter. No hearings take place at Mini/Junior level below U13s, the club is deemed capable of carrying out an internal investigation.
Working on the premise that ‘foul play is foul play regardless of age’, one has to be careful in the delivery of the card. A dangerous tackle or a reckless stamp etc, could warrant a red card in any game but you could be empathetic at the lower age ranges.
Punches, and the similarly offensive strikes, and abuse (especially MOA), a red card should be in the refs mind. I have had a couple of hearings for U13’s for MOA and it is creeping into the game!
As refs and coaches, we try to keep young players on the park, and no ref should ever say ‘you leave me no option’...there’s always an option! Refs should ALWAYS fill in a red card report...even though they may think afterwards that it was too harsh.
That is for the Discipline hearing to decide any sanctions/tariffs that are necessary.
So I would exercise caution in delivering any cards, but there may be overriding circumstances that drive you doing so.