I would think a Dunn and Bradstreet (D&B) report might give a better picture of a companies "health" than guessing about some bill not being paid, I know plenty of healthy companies that have firm rules about paying a bill when there is no invoice signed that has had them put on some vendor's "cash only" lists, that had -nothing- to do with 'could the bill be paid".
-Bouncing- an employee's pay check should be a sure sign the doors are closing, at least in most states in the USA.
Kind of like when the IRS puts it's own pad locks on the door, is a good sign the company has some money problems.