Generally speaking, all racetracks, when considered private property, which they all can elect---even those owned by a state (like the Meadowlands used to be, vis a vis the NJSEA)---have "property rights" and the right to exclude. Yes, appeals, right to one's livelihood, etc., can be argued; but it's going to take a massive amount of litigation. The problem is racetracks either:
1) Turn a blind eye and a deaf ear
2) Sweep it under the rug, for selfish, self-serving, etc., reasons
3) Management is inept and don't know how to properly operate and run the business of a racetrack
4) Rely on others to enforce and govern
5) Are simply stupid.
That said, below are some links regarding exclusion, specifically Jerry Hollendorfer being excluded:
https://www.thoroughbreddailynews.com/private-property-rights-under-hisa/https://paulickreport.com/nl-art-1/can-they-do-that-the-legal-precedent-or-not-behind-hollendorfers-exclusionhttps://papers.ssrn.com/sol3/papers.cfm?abstract_id=1676884I don't intimately follow DE racing, but I am not surprised. Simply more like PA.