Yes, you can be found liable.
You should also discuss this with your insurance representative to make sure your liability coverages are sufficient to protect you in case of a litigation situation. The legal department of your insurance company can also give you advice on your form. Forms are available on line. Just do a document search for Hold Harmless Agreements and Liability Releases. Edit to your needs. Prepare the form and then take it to your attorney who can edit or add as necessary. It shouldn't cost you much money and you can probably do it all by email.
Then, have any guest (riding or not) who enters your facility sign the release forms. Minors must have a parental signature.
It is always interesting to watch the faces of people who are reading to sign my forms. There is a paragraph that discusses the inherent dangers associated with equine and farming leisure activities, horse behavior and the possible situations that can occur with any horse that can cause injury or even death.
I do not have my service providers such as vet, farrier,osteo, etc. sign the form but it is enlarged in sign form and posted throughout the common areas.
In the long run, this is a minor investment which will protect the assets of you and your family.