Translation:Many cars and buses are parked at the expensive hotel.
How do you know when áll is expressing movement and when it is expressing a fixed position? In English "stand" means a fixed position. (The only time I can think of when it includes movement is when we say "stand up" or "stand down".) I get that "áll" is used to express more ideas, especially when used with preverbs but I have trouble sometimes knowing when movement is implied or not. In this sentence I can also see the meaning that the cars and buses are parked instead of parking. Does the suffix "nal/nel always indicate movement taking place? Is that how I know in this sentence to say "are parking" ?
I think this sentence means "are parking" as "are standing there, parked". It's not a movement. It's probably just a slight mistranslation which even I, as an English speaker for over 15 years, wouldn't get straight. "Is parking" sounds pretty stationary to me.
Áll is only used as a movement if there is a source or goal given, i.e. one of the noun suffixes or postpositions that indicate movement, and/or if áll is combined with a verbal prefix. Neither applies here, so those cars are indeed parked.
-nál/-nél just means "at" or "by" or "happening in the general vicinity". No movement indicated.
Tony, áll means "to stand", but you don't usually say "stand" in English to refer to something that a car does. So you have to get a bit more creative with your translation.
"To park" has its own Hungarian word, parkol. The verb áll doesn't specify if the car is parked or is waiting with a running engine.