dastarkhaan

Q:

1. Must food be covered while it is being carried to the dastarkhan from the kitchen (for the meal)?

2. Must the uneaten food be covered while it is being carried from the dastarkhan to the kitchen (after meals)?

3. If so, what is the Shar`ee status of this practise?

Q: Is the food that has fallen on the dastarkhaan which we are encouraged to pick up and eat, the mahr for the hoors of Jannah? If not, then is there something to this effect in the riwaayaat?