I am an exempt salaried employee. My employer announced in an employee meeting today that if we are even 5 to 10 minutes late that we must use 30 minutes of sick/vacation time or we will be docked 30 minutes even if we are required (as usual) to work late. According to FLSA wouldn't that move us to non-exempt status?

Your employer can require you to substitute paid time off for tardiness. However, if you do not have it available, docking your pay for a partial day under these circumstances does jeopardize your exempt status. You might want to show them this, which explains the situation under which your pay can be docked:
http://www.dol.gov/dol/allcfr/ESA/Title_29/Part_541/29CFR541.118.htm

If they dock your PAY that is illegal for exempts. But docking your sick, vacation or personal time does not violate the FLSA for exempt employees.

Of course, one way to resolve the whole situation is not to be late.