I am 34 years old and have been to Disney nearly every year since I was born at various times of year including summer. Never had I gotten one. single. mosquito bite. UNTIL...Sept 21st-25th. My husband and I came home absolutely covered from head to toe in bites. From our research, there was a huge boom in the mosquito population after Irma (excess standing water, etc) that Disney mosquito control, and Florida in general hadn't had time to catch up with. Had I known that before our trip I would have brought Sawyer Picaridin lotion. It's the best. No point in using anything else.
All that being said, we can safely assume that all bites were received outside on our balcony or patio at night because our early-to-bed toddler didn't get one bite the whole trip. So if you're not going to be out at night sitting on a balcony, you'll most likely be fine. I think we got a few one night at the pool, but nothing compared to our balcony bites! Ha.