So "picking up" would mean that I found it (where the system thought it was), and I physically got it and logged it as such. Anybody who wanted to know where that partciular TB was would know that I, personally, had it in my grubby little hands, and that I got it from a specific cache.
OTOH, if I "grab" it, it means that I also have it in my grubby little hands, but that I didn't necessarily get it from the cache where the system thought it was. By some quirk of nature, I have come by that TB, and I now "officially" have it.
Is that pretty close to being it?