@McTag,
No - absolutely not. Bonuses are supposed to be paid according to work that is done above and beyond their normal job expectations (at least that is what I am told at work). Isn't that what bonus means in a sense - it isn't supposed to be guaranteed pay.
I am on the fence about severance - if some one is let go, even at a low level and even an underperforming employee, they receive severance (at least that has been my most recent experience). However, severance should be determine comparable to all employees.