Funny thing is, if I think back to that Good Friday long security clearance queues, I recall a lot of people asked to remove shoes after walking through the body scan archway.
I rather security be tight and flights protected from terrorism but at the same time I do tend to find SEN are definitely more fussy or the machines too sensitive. I can get through LHW T5 or City security fairly fast, and never had anything like the frequency of secondary checks that SEN seem to ping at high levels of reoccurences. Does seem very strange.