I am trying to learn more about Bitcoin.
I was looking at this video to understand how a "double-spend attack" is kept from taking place on the Blockchain (in Bitcoin).
https://youtu.be/Lx9zgZCMqXE?t=12m13s
In this case, Alice might send money to Bob to purchase an item.
Alice may use the same input to send money to Joe for another item at the same time.
It then becomes a race as to which one will get approved and which one will get rejected (the one sent to Bob or Joe).
It is my understanding that a "double-spend attack" could not take place because all of the nodes will be working at the same time.
I have heard of transactions not being processed for days because of a low miners fee.
In such a situation, would not this allow ample time for a "double-spend attack" to take place?
TIA