I've had an 'agricultural violation' in 2010 where I forgot to declare an orange on my customs form, then remembered about it between immigration counter and customs, and declared it to the customs. He told me off, wrote my info down in some book and [obviously] confiscated an orange.
In November I applied for GE, got approved and last week, during my GE interview, this was mentioned [and was warned that I could lose GE if I do this again], but it didn't affect them approving my GE.
What was interesting is that this offence was with a different nationality/passport than the one for my GE application [under the same name].