everyone who breaks the law, a rule, a policy or similar is usually taking a calculated risk that 1. they won't get caught, 2. if they do get caught the punishment is something that they can live with.. or 3. risk is not taken.. i understand there are the occasions one truly did not know or was given bad/inaccurate advice.. but lets go with what we can control in this post

As much as this applies to an 8 yo kid on his wireless DSi or PSP.. it applies to our every day life. Ever exceeded the speed limit > why > you needed to get somewhere quicker > risk was getting caught by the cops or an accident > your spot on the risk cube was like A1/B1.. low chance of happening , low consequence or Probability was very low and the consequence of a ticket is low (accident probabiity is even lower with a higher consequence) but in either case still in the green boxes of acceptable risk.. every time we go outside the lines we make this risk/consequence analysis.

When the parent let the kid (assuming she knew the rules.. its reasonable to assume that she might not) use the wireless on the PSP's.. the risk was interference with the aircaft.. P= almost nil/consequence aircraft malfunction.. in this case.. the P being so low that it overrides the malfunction risk.. or risk number 2 being arrested by police on the ground for violating some rule with a consequence of arrest and all the comes with it.. again P<extremely low; finally risk that FA will say something and take away PSP < low with a consequence of losing PSP for flight.. again low.. FA not likely to take it away on first request..

no matter how you slice it.. most every rule thats broken is just a decision made as to the risk/reward of doing that.. hence going back to what PresRDC said.. or at least a spin off of it.. you need to know what you can and can not do.. to listen to certain people or not.. and to make decisions you can live with.. and assuming this parent knew the rules.. she made a decision she could live with.. for all we know she was willing to go as far as waiting till a FA told them to turn off the wireless and would have stopped it right there..

I know with my kids.. when the electronics are told to be turned off at departure.. I know the FA's are going to come by and check on them (as they do every seat).. the kids are playing from the moment they sit down at our boarding.. when the FA tells them to turn them off they do without a whine.. sometimes (not often) the FAs don't tell them too.. and they keep them on..