Primary: I've seen some spectacularly dim/harmful 'old' wireless solutions largely because the science, that there actually is a science you need to grok, went right over their tech-support's heads. Tech comprehension has slowly improved though and if they move from old cheap 2.4GHz kit then it's inevitably to managed wireless - there's been quite a lot of that moving in the last couple of years.
In previous research / reports problems with WiFi had a significant impact on faith in the technology as well as functionality. <snip> The bands used might have changed, but has management of it changed that much? Is there a difference in that between primary, secondary and special (and the other variants in between)?