To answer the first part of your question, you are correct. You would only have one round-trip trade.
I'm not sure about the second part of your question, so I will have to guess. I am guessing that these people are trading on margin, which is someone else's money. This is a dangerous thing, and it would be best to wait for the money to settle even if it might be a little frustrating.
HTH,
Jeff
"The greatest mistake you can make is to be continually fearing you will make one." -- Elbert Hubbard (1856-1915).