In that case it is enough money (legit mid 6 figures) that hiding that would not only be difficult but probably felonious. Their treasurer/accountant would be insane to not report it, just hoping nobody goes that deep into the 990. Read the first page and it looks like they are just getting by, trying to break even. The devil is always in details. In my opinion schedule L info should be on the first page of a 990, not buried 20 pages deep.