Any problem with dragging/dropping specific data from mac to ext hdd?

Is there any danger from dragging and dropping specific data (in this case new photography raw/jpegs/layered photoshop document/possibly tiff files from my macs internal hdd to the external hdd, then deleting the one on the internal hdd.

Is this an okay practice, I guess is what I am wondering.

Also another question. Sometimes I don't have the time to view and edit my photos so I need a temp storage solution I would like to use an external hdd to temp store certain photos, then later go through them and delete them. I use adobe bridge for this to initially weed out my howlers from my keepers. It throws them in the mac os x trash and then I can right click on the trash to delete permanently. Is there any danger doing this as well (other then being careful to make sure I 100% want that data gone).

Thanks in advance!