They can. Your rates are based on several factors besides a "spotless" record, things like change of address, new members of your household, availability of your vehicle to other drivers (such as a teenager)...even if you smoke.
Why? Let's look at a common question like how many miles you drive the vehicle. When you bought your policy, you might have had a job that, along with your normal driving, only required you to drive your vehicle 100 miles or less each week. But since then, you might have changed jobs and now drive 200 miles a week. This would obviously increase your chances of having an accident, since you're on the road more often. An increased risk like that would require an increased premium.
Still, factors like the above are relatively minor, and with a spotless record, you should be in good stead as far as your rates are concerned. Even if you saw a rate increase due to the answers on the questionnaire, it would probably be relatively minor to, say, someone who just got a DUI.