WARRANTY question !

Z11

i bought my Z in april so it hasnt been a yet just yet, but my fuel cap door is malfunctioning.
has anyone gotten their Z's serviced at a nissan dealership? or anywhere else and get the Z checked every 3 months or every 3K intervals like it says? im sure this problem is covered by nissans warranty, but i barely drive my Z and i dont see a reason to get it checked every 3 months or 3K, so if i take my issue to the dealership i bought it from, what will they ask me about where i got the maintenance check done, and wouldnt they want receipts for the every 3 months? i did a maintenance check in oct 2012 (6months) like the dealership told me to get it checked at and not the 3 that it says on the booklet. jan 2012 (9 months) which i barely drove because of the snow, and im waiting for april (12 months) to get it checked again.

so since i bought the Z ive only got it checked once, what will the dealership as me for if i bring them my issue, will they ask for the receipt of my maintenance check and then ask why i dont take it in every 3 months, then void my warranty?