Staff cars parked on street with car park left empty

[bestfakesmile]

Opposite my house is a business which has a large car park for staff. However, two particular members of staff always park on the street directly opposite my drive which makes it very difficult for me to get my own car out.
I have approached the staff politely when they've been parking their cars and they have said they won't park on the car park as the tree (think it's a cedar) drops needles on their cars. They variously say the needles have got 'inside' the car and/or damaged paint work
Their cars are both 5 years old but the manager does park his brand new car under the tree every day without any apparent issues.
There are also several spaces on this car park that are not under the tree but they won't park in those either, not sure what the reason could be for that.

There's a few places in my works car-park where I'd rather park out on the road than in the space. The first couple are under a tree where you can guarantee your car will be coated in birdcrap and bit of twig and needles that produce some sort of sap that pretty much glues them to your car. The other spaces are either side of a gap in a hedge where people will walk through with bags, etc and people have had their cars scratched.