I looked on the wiki already and all it said was:

If a player dies with the blowpipe, all scale and dart charges will appear on the floor along with the blowpipe.

If you die with it and you have protection on when you respawn, the darts and scales are still in it right? 

Yes they are still in it but if something protects over it the darts and scales also hit the ground.

You can test grey sections of death mechanics like this with a friend you trust. I used to test some stuff out with a IRL friend of mine.

Ofcourse you can also double log on two accounts, assuming you have two member accounts. (double log is done by simply logging them both in quickly after eachother)