For me, it's the stories about a team cooking the books. Either to pay the coach more, or to give a kid a free ride and have the other parents unknowingly pay for it. Also, lots of examples putting a parent on the staff so they can have financial gain at the expense of other parents. Basically, if they have to hide what they are doing, it probably qualifies as corruption in my books.
Also, that story about Niagara drafting all those kids off the same minor hockey team/same agent so they could get university offers.
Getting sponsorship is a good thing if there are no strings attached. But that's not always the case.
Open borders will make things interesting. Likely more free rides as players can truly go anywhere. If the money comes from sponsors, great. If it comes from other parents, not great.
+1 to parents ruining it for everyone.