Yes. So one should read the signs and do what they tell you to do. Not very hard to comprehend is it?

At LGW South, different lanes have different procedures depending on the equipment in use. Some require laptops in bags, some out of bags, some shoes off, some belts off, etc... It is all signposted as you approach the machines however. The people who stop to read the signs usually get through a lot more painlessly than the travelers who try to rush through and complain that it was different the last time.