If the 2.5 yr old is getting off the chair thrn put her in a booster seat with a seat belt so she can't get out I think if you use a firm voice and stay consistent she'll get it ..... If she gets the same reaction from you every time she will give in. I only have full time children and I wouldnt accept a child for two hours especially during nap time if they are not napping they would gave to cone and pay for half days so I can't help you with that one.