There is no one magic bullet with tick prevention. Tick tubes are good, but not really effective in my opinion.
find out what spray they are using; almost certainly it is permethrin.
After 4 bouts of Lyme, 2 of ehrlichiosis in myself, and two of my boys having Lyme I sprayed around the barns a few years ago. I’d think of continuing this except the cost was pretty high.
I agree with you OP that natural does not equal safe. However, I did do research on the permethrin spray and it apparently breaks down in sunshine in a matter of hours. In other words, it has less residual effects in the environment than other pesticides. I had a whole discussion with the spraying company about Rosemary Oil – the University of Maine found it to be a very effective tick repellent. However, as far as I could tell no one was using it commercially (though this was a few years ago).
I found a notable reduction in ticks with the spraying.
I agree with LauraKY, it is worth taking serious measures to deal with ticks.
The tick tubes, spraying, mowing grass, removing leaf litter, having a border area , not feeding birds (ticks drop off them into otherwise “safe” lawn areas), wearing permethrin treated clothing if you are working outdoors, or, removing your clothes immediately and putting them in the dryer for a hour or two, showering at night, doing tick checks (though understand that this is not at all fail safe and you can easily miss tiny ticks), and finally, taking a couple of doses of doxycycline if you’ve been bitten are all measures you can take (and I do).
(PS the doxy within 24 hours of a tick bite is accepted by all medical professionals (it’s been studied) but there is some disagreement over how much/how long to take the doxy. The one study showed that one doses of doxy was effective (but not 100% effective) and there have been no other studies of whether or not two doses, or two days (4 doses) or a week would be more effective.)