There is nothing wrong in doing so as long as it does not in any way involve any disrespect to the symbols of Islam or the rites of hajj. Teaching through illustrations and playing out the various scenarios for purpose of education and reinforcing ideas have some basis in the Prophet's own precedents, for we know that he used to demonstrate and use gestures to communicate important ideas. Furthermore, the Prophet's method of instruction and teaching, as eminent scholars have stressed focused on practical demonstrations, rather than lecturing or preaching.
We also learn from some reports that both Hasan and Husayn in order to correct someone who performed ablution incorrectly, played out the scenario, one of them thus making mistakes, and another correcting him while the man watched! In this way, the man was taught the correct way of wudhu while not undermining his self-esteem. On closer examination, one can find similar precedents from the Prophet (peace be upon him), especially in his exchanges with his own wife 'A'ishah (may Allah be pleased with her).
In conclusion, there is no need to be rigid on this, as long as they do it correctly while imparting reverence for these symbols and rites in the minds of the children. After all, children learn better through practice, rather than through lectures.