I have been reading the PET book (Parent Effectiveness Training) book and have only dibble dabbled in it but from what I have read it would suggest that you do tell them something (following PET they are never too little) - it works on the principles that you don't always have to be consistent and explanation and communication is the key. If I get chance I will find the bit that I think was relevant - I can't do it justice trying to explain - but Mayaness I know has read it and I think BellyBelly Kelly too and might be able to explain better than me.