Let me add to what you quoted to help put it in context. If there is any sort of pressure storage after the BIRM filter (flexible piping, expansion tank), dropping the pressure suddenly and significantly before the BIRM filter can cause a reverse flow, the effect of which could be to unsettle the media pack. Something like solenoid valves on a sprinkler system could, depending on the volume, do that. A simple garden hose would not likely be a problem. I have one hosebib connection before my BIRM filter and several others after it. The ones after it run my soaker hoses on timers.
I also have a full port ballvalve Teed in just before the BIRM filter that I use to purge the line of iron buildup. When I actuate that valve, it does unsettle the media pack and I get iron bleed through to my softener. I periodically purge the line just prior to a manual backwash so as not to cause a problem.
If you install a checkvalve, then you will need to have an expansion tank as it becomes a closed system.