Sunblock keeps the harmful rays of the sun from penetrating the skin. However, sunblock does NOT keep one from tanning. If it's hot enough in a building, you'll tan or turn red...depending on the melanin in your skin.
I would have said something to the parents about the children had I seen that, but that's just the type of "mom" I am.
I'm always telling my daughter's to load the kids up with sunblock before they are going to be exposed to the sun, then apply an Aloe Lotion or after sun exposure cream/lotion once they come out of the sun. Whether they listen to Mom or not...well.......parents of adult kids know where I'm coming from with that statement.
I used to lay out in the sun a LOT between my 20s and 30s because I don't like looking so pale, especially in the summertime. Since reading about the many cases of skin cancer over the past ten years, I've not laid out like I used to...therefore, I'm not as brown as I want to be anymore.
I think I was about 30 when we were vacationing in Florida on the beach. I fell asleep while tanning in the lounge chair. When I woke up, my skin was very hot, my legs later swelled, my upper limbs were also tender to touch. As the day progressed, I was in so much pain I couldn't stand wearing clothing. I put tons of Aloe Lotion on, bathed in tepid water with baking soda in it, and ended up going to the doctor after returning home. Never since that time have I fallen asleep while sunbathing. My husband (at the time) was told to wake me up if I slept more than 30 minutes in the sun. Lo and behold...I wake up to find him GONE...too long in the sun was his complaint, but he LEFT me to die in the sun I guess.