I agree. While there's certainly nothing wrong with this app, it simply shouldn't be necessary. Keeping files in your trash is just stupid. Do you store food or mail you still need to read in your trash in your home? Of course not. Then why do it on your computer?

One can have his reasons for not empty his trash immediatly. I myself like to empy trash only after ending a job. Smart Trash gives me the opportunity to delete trash only for one specific disk. Very usefull since I've only about 4 internal and several external. And do not forget about usb sticks too! So very handy indeed. And very hard to solve in the way you mentioned. But if you know some other way or app, I realy would like to hear from you ;)

Years ago there was a movie made about a fad called Flatliners starring Julia Roberts that was about medical students stopping their hearts short period of time with their friends resuscitating them so that they could experience death. While interesting and satisfying the curiosity of the recipient it still was very dangerous thing to do. This is the same way I feel about Smart Trash. In your scenario I would suggest creating a 'recycle' bin on each of your drives that you could place in the left hand side of the Finder window. Then at the end of your project, trash the folder and make a new one after removing any desired contents. Flash drives are not an issue since trash on a volume can be emptied only when the drive is found.

Another another alliterative is to label files to be trashed with a color label (single right mouse click). Then at the end of your project use the 'Find 'command to find all the files with that label, remove the label from the files to save, then 'select all' and move the remaining to the trash.

The bottom line is that I still believe that using Trash as a storage receptacle is really a bad idea. The only reason I believe that Apple made its contents recoverable is to allow users to recover a file that was accidentally thrown away before it is gone for good.

However if using Trash as a temporary storage bin is 'what floats your boat' then go ahead. After all it is your boat. However I would strongly discourage others from following sail as they might find themselves 'rearranging the deck chairs on the Titanic' when they accidentally hit an iceberg.