When the 'expert' paid to do the job stuffs it up.
The cheap DH bike I bought had receipts for the forks being rebuilt. The seals and everything look mint and it works nicely, so seems OK.
I figured that since then, someone had been tinkering and had the front wheel off since as there was grease all over the bottom of the fork, the end of the axle and the hub. Also the pinch bolts that hold the 20mm axle were all in upside down, so were doing absolutely nothing. (They were extremely tight in the now stripped steel retainers too, so had been way overtightened, probably because the axle was still moving around.)
On the weekend I went for a ride with a mate who's just had the first free service done on his bike at the same shop. It had the same colour grease all over the frame around the rear axle, leading me to think that it's highly likely the same shop was responsible for all the grease and the upside down bolts. My mate wasn't impressed as they has managed to botch something on his bike too that luckily he was able to rectify himself.
Bikes aren't that hard to pull apart and put back together. There are a few tricky parts, but the shops shouldn't be stuffing up the easy bits...