Horizontal lines on my Screen

My Macbook Air's screen has horizontal lines a few days ago and when I called Apple Help Desk, I was told to update the software but it doesn't solve the issue.

Went to the Service Centre yesterday and the technician suspect that it could be water spillage. This Macbook was only 4 months old and I didn't even spill any glass of water accidentally onto the computer. Don't tell me the computer cannot withstand a few drops of water if it happens to land on the keypad? I have been using my old Macbook for 6 years with no issue but the recently model is really no longer durable like last time. It is really a disappointment.

Doesn't anyone has any issues with your screen for the new model?