I've voted no. I would class myself as being a bit clued up about mobiles and I make full use of my mobile. However, my mates see me as some sort of phone freak and a 'know it all'. Now I know that this certainly isn't the case and there are many more knowledgeable people out there (just look at this forum for example) and therefore is the reason I voted no.
If I use my mates as a group of average people then they have a little interest in their phone, make reasonable use of it technology, but, and here's the clincher, if they put in another network's sim card and it didn't work, then that would not bother them. They would either switch networks, or get another phone.
I do believe that the networks are entitled to sim lock their handsets, but the customer should be able to get it unlocked, at reasonable cost, from day one.
Or you could just buy sim free like Ben, or from O2 like I did