It is funny how much they stand out to us former JWs, yet other people barely notice them unless they try to push literature.
In the clinical literature on trauma, the JWs would be likened to "conditioned stimuli": We're more attuned to seeing them and reacting because most of us here have a lots of negative, if not traumatic experiences with the JWs. To use the lingo, the JWs are conditioned trauma stimuli: As soon as we see them - or think we see them - upsetting old images, thoughts and emotions are stirred up inside us. It seems as well that for many of us there is an urge to reach out to the JWs perhaps to show them we're not the bad people they've judged us as being.
That's why people who've been victims of physical and/or sexual crimes, find themselves automatically reacting if they go somewhere and someone who looks like their perpetrator is present. Often we can be left feeling hypervigilant and unable to shake the upset feeling for a time. For me, as the decades pass, I am more accepting this is a completely normal reaction (given my experiences with the JWs) and I seem to get over it sooner. Also, my days of trying to reach out to them, say, in public settings, is well and truly over. Part of that is because I need to look after myself - and, really, it doesn't help trying to reach out to people who have an equally automatic fear response to ex-JWs.