Yes it is a design anolomy.
When the car is on level ground you can lauch things off the trunk lid when it opens, but if on a slightly steep uphill stance the lid will tend to come back down or even if it is windy.
The springs are two rods located just under the back window where the hinges meet the body. Mine are set in the middle of 3 notches. The tension could be increased by one notch but it isn't easy to do.
I think if the tension is too high, you could do fatigue damage over time.
In Taylor'* case though, he may be wise to increase the tension one notch.