Yes teens need authority but if you bring it in an adult way chances are they will actually listen instead of snooping behind your back. And yes if a teen really does something wrong you should indeed ground them or whatever. But if you speak to many times on a authority tone the effect will become smaller since they know that it will happen anyway.
And according to the psycology a teen wants to break free from their parents and if a parent is above against (offesive) (rose of Leary) which is the normal parenting style when the child is younger (they need it at that age) a child will need to break free to become an indevidual and go opposite from their parents style and become above together in the hope that their parents wil get more balanced towards the centre of the rose. so offense leads to offense. If you approach them in an adult manner which is somewhere near the centre of the rose they will be more open to arguments since they don't feel the need to have to break free from the parents and so they don't have to put all their energy into having to break free. (below I will explain the rose of leary a bit better.)
I just don't think porn would be the thing you would ground them for because it then gets more interresting. since they know that porn is a pleasurable thing to do. Again any teen knows there is a multi biljon dollar industry and many of them (and not only boys) will have masturbated at least once at age fifteen. (again I base myself on accounts of myself and my friends.)
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Rose of Leary
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The rose of Leary consists of 2 axis --> above below and against together
against | together
|
above |
---------------------------+-----------------------
below |
|
|
therfore there ar for combinations possible:
above-against or offense (e.g. why did you do that?)
below-against or defense (e.g. but I just wanted to ...)
above-together or leading (e.g. would you do that please?)
below-together or following (e.g. yes)
a natural reaction wil always be above leads to below and vice versa.
a natural reaction to against wil be against and together leads to together
so offense wil lead to deffense and vice versa and leading will lead to following and vice versa.
But if someone is very offensive or defensive or leading or following you might want to change that. You effectively want to change it towards the totally oppesite so that they become more towards the centre of the rosefrom offensive more towards following for example.
If you want to achieve that you will need to become the same above or below cathegory but the other against together cathegory. so to change offense you will need to assume leading role. If that is in a parent teen situation it will probably clash.
I hope my explenation of the rose of Leary is clear and that it explains why you should talk to teens as if they where adults