By Anthony Reuben
Business reporter, BBC News
It is Saturday night and you have settled down to watch a DVD.
There is often little point in putting this notice on a DVD
You have waited while the player fires up and then starts reading the disk.
Then, just when you think you are going to get some entertainment, instead you have to sit through the copyright notices.
You try in vain to fast forward or skip them but you cannot.
So does it need to be there?
"Having the copyright notice there increases the damages that can be awarded if you subsequently infringe copyright," says Niri Shan, head of media law at Taylor Wessing.
"In the UK you can get what are called 'flagrancy damages' if you knowingly copy something you shouldn't."
But if you ran off a few hundred copies of Twilight on DVD, it is hard to imagine you could get away in court with claiming you had not realised it was covered by copyright.
"The main reason for it being there is that it removes any doubt," says Silas Brown, a solicitor at the intellectual property specialists Briffa.
"Without that notice it should still be a copyright work, at least in the UK."
At least you no longer have to sit through the once unavoidable anti-piracy trailer that used to precede all DVDs.
It stated that you would not steal a handbag or rob a bank so should not copy a DVD.
"We did get criticised for the trailers before films, so now you just get the copyright message," says Eddy Leviten from the Federation Against Copyright Theft, the organisation behind the trailers.
"They were effective at the time but now we have got that message across."
The federation is now pursuing a different message with its "You Make the Movies" campaign.
At your own risk
If copyright notices do not make any difference, what about other legal-looking notices you might see?
There are signs all over the place saying that particular organisations take no responsibility for things, or that people enter somewhere at their own risk, but they do not necessarily make any difference.
There is some question about the value of warnings such as this
"You don't automatically absolve yourself of liability," says Des Collins, senior partner at Collins Solicitors.
"You have a duty for public safety and the reasonableness of the sign will have to be assessed by the courts."
So if, for example, you entered a building and were electrocuted using the doorknob, it would not make any difference at all whether there was a sign saying you entered at your own risk.
Indeed, a sign outside a building simply saying that you enter at your own risk is of almost no value, according to Mr Collins.
"The wider the warnings are, the more they satisfy the person who put them in place and the less they satisfy the requirements of the law," he says.
Another sign you will often see in cloakrooms is one saying that the management takes no responsibility for items left there.
If somebody walked in off the street and stole your coat, the owners of the building could indeed probably avoid taking responsibility.
But if, for example, your coat was stolen by a cloakroom attendant who had convictions for theft, the owners would be liable, and the sign would be of no value.
So however legalistic and official a notice may look, there are all sorts of circumstances in which it will make no difference at all whether it is there or not.