Welcome to the Forum...
Your friend is in a bit of a bind, however, it is one the "boarder" is taking advantage of her and needs stopped, NOW!
So in the early 1980's I managed a barn...with a large indoor arena.
We allowed outside instructors to teach.
Instructors had to have their own insurance policy that had some clause that we were not held responsible for " ?? " not sure as I never saw it but it was drawn up by a very savvy lawyer.
Outside instructor had certain hours they were permitted to teach lessons, and they had to schedule them at least a week or more in advance... the indoor and facility were for our boarders not worked around the outsiders convenience or schedule.
Every lesson not with the facility instructors who were all excellent credentials and abilities paid a ring fee... at that time it was $15 per lesson....who paid it wasn't our responsibility, but it was paid by someone!
Outside horses before unloading were coggins checked and vaccinations checked and looked at to make sure they appeared healthy since they arrived from other locations.
All outside horses arriving paid $20 per horse PLUS a instructors fee of that $15, so = $35 before you even started...
Fees were paid up front, not after.
Those who wanted to ride with "XYZ" could at the barns schedule of convenience and thy paid the lesson fee if they boarded.
At any time they were free to ride, but once that instructor said one word, or arrived in the ring to teach the fees started.
Fast way to lose your borders is to not allow them to use the facility they pay for because outsiders are forever in it on outside horses or lessons being given.
The answer is a working schedule....
Hours of this instructor teaching are on off hours of arena use... mid-day, later at night.
Not prime time nor weekend when it is prime time for boarders to be about with their horses.
Strict enforcement needs done and some of that is also who may be in the barns doing what....outside horses should not be inside your barn bringing in germs, bacteria from other locales...good way to make your horses sick...it takes only one oops.
Outside riders also don't need to be wandering your facility or grounds...good way for things to go missing, used or "lost"...
But indeed, someone is taking advantage and now building their business on free policies needs stopped and reverted back to it being advantageous for the farm to have facilities...
Either that or the farm gets a healthy share of the revenue from every ride, every lesson given whether it is on a boarded horse or a trailered in or a walk-in student....
Today those costs were start at $25 per lesson given and horses brought in at $40 per animal per lesson given...those fees might be more too as I've been out of the "working in the industry side" now for many years.
When lessons cost upwards of $100 in many locales....well, all is relative in what they will pay!
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