For any slightly complicated project on a house the estimate assumes everything goes right, which everyone knows it probably won't. It's just a starting point, not a commitment.
Definitely so. Most business people that I've worked with do understand that. And provided problems are communicated early enough can manage expectations.
Where I've seen issues is when there is a big disconnect and they don't hear about problems until it's way too late.
Where I've seen issues is when there is a big disconnect and they don't hear about problems until it's way too late.