You guys thing that ESTA is so automatic and online? 8 out of 10 times that I have witnessed people are asked to show their ESTA at check in or the gate when boarding despite it supposedly being automatic and automated, it perhaps adds a few seconds to the passport check that they regularly perform anyway, so I cannot imagine that it will be a huge problem in the other direction. Regarding the whole "spouse" thing, please refer to what GU wrote above.