Walking, I'm sorry if you felt I was unhelpful.
To elaborate, perhaps we are talking at cross purposes. When I was teaching, the importance of involving parents was emphasised repeatedly, going as far as 'make it their problem' (this is the mantra at many schools.)
Parents have far more sanctions available than teachers. Confiscating toys, technology, limiting tv time, grounding, pocket money stopped to name but a few. All teachers can really do is tell off/keep in at play (often counterproductive for disruptive children anyway and means the teacher loses their chance to have a wee!)
Also, most children (most, before everyone shouts me down) despite appearances are desperate to please mum and dad.
The responses I used to love when teaching (and this was secondary) were:
'I will certainly have a word with him/her!'
'Don't worry, Mrs X, this behaviour will NOT continue and if it does, please let me know!'
'I have taken her iPod off her, and she will get it back as soon as you tell me her attitudes improved!'
It's that 'no,we will not accept this and we are behind you every step of the way' that's so valuable.
Discipline of the child ultimately is down to you, the parent, and I'm saying that nicely (and I am far from strict but I will back the school to the hilt if needs be.)