If the sonographer's are looking at nuchal thickness, then they are doing a screen. This is ok if you are happy for it to occur and it all looks good, BUT if you have stated that you don't want the screen (and don't want the info that measuring the NT can bring) and this is done then you may be presented with info that you didn't want to have.

All ultrasounds are done to look for things that are 'out of the norm', and people should be aware that this is their real purpose, not to give parents an opportunity to look at their baby.
Kate, I realise that this is the purpose of the scans. Having a look at DD was an added bonus for us . We were there for a dating scan. It wasn't an NT scan and was not backed up with the usual blood tests.

There are additional ultrasounds you can get though if you just want to have a look at your baby. I won't begrudge any woman who wants to have a look at their bubba! It is a great stress relief and a wonderful way to bond.