Well there are already clear examples of people being targeted for laptop border searches in a premeditated fashion. i.e. I can't get a warrant for the computer

Well there are already clear examples of people being targeted for laptop border searches in a premeditated fashion. i.e. I can't get a warrant for the computer of citizen X, but I know s/he will be traveling outside the country and coming back on date Y through airport Z. Since constitutional rights aren't respected at borders, I can simply instruct airport Z to detain citizen X, and seize their computer equipment and copy it. This isn't even just about what happened in the UK with David Miranda. There is at least one well documented case here in the US involving a guy named David House. These actions are definitely a step along the slippery slope of legitimizing other practices. Plus, it is entirely possible that our intelligence agencies have already targeted some individuals very specifically for neutralization somehow. We can only confirm that they have not done so through transparency and oversight.