cjhants:
That is the major shortcoming of the system. Clearly when the scheme was being discussed, all the people around the table were tech-savvy and never for one moment considered that people aren't barred from travelling to UK. And as you quite rightly say, handing someone a tablet and expecting them to use it is fanciful.
highflyer40:
It would appear that the training for UKBA officers before the system was implemented went something along the lines of "use your common sense; if someone proffers their device to them they have clearly filled the form in, and therefore let them carry on, if they look at you quizzically be suspicious and ask questions". Fact is, if you've filled it in you could put any old garbage on the form if the officer isn't even going to give it a cursory check. We have driven back twice since July, filled in the confounded form out (honestly and correctly) twice, and both occasions been waved through.