Ever received a birthday card that was whited out and then written over again? You have an accountant friend.
White out, along with other tools such as calculators, rulers, and binder tabs (all stuff for future posts) are key staples of the accountant trade. Accountants tend to write with specific colored pens, and rely on white-out when they make mistakes. Either that or reprint the ream of workpapers. (Both happen a lot.)
Amongst accountants, white out is considered an art. Experienced accountants have a greater level of skill when it comes to whiting out specific numbers in tiny text or the little area between boxes. The less experienced accountants have to rely on whiting out the whole section and then recreating it by hand.
You can use this to your advantage by having spare white out available. To an accountant, this says that you are a person that they can count on in their times of need.