I don't know how it works in Denmark but I've seen that being worked around all the times.
A typical thing is to make a special model just for the sales, which is the same as the normal model with maybe some small differences like firmware tweaks, different accessories, different stickers, etc... They put one or two samples in the corner of the shop at an inflated price, not intended for anyone to actually purchase, then when the sales come, they unload the truck and proudly show the new "discounted" price.
This way, they can justify that they had the product available for a long time, that it didn't sell, and they can officially make the discount.
They don't even have to keep stock except for the one sample. You can get a funny situation sometimes when someone actually wants to buy the sample at the sticker (inflated) price and the shop actively tries to discourage the customer from buying it despite the huge margin. That's because without the sample, they won't be able to justify the "discount" later.