I guess an Auto-Ignore when the respective Material Storage is full is in order. As soon as it isn't full and the Player hasn't manually ignored it, it shall continue scooping it then.
After all, Data Scans into a full Inventory also don't stall any subsequent scans. Those are auto-ignored already.
PS.
The all-manual UI Ignore/Unignore selection that only works when the respective item is already floating (and Target of Collectors) seems extremely clumsy.
- there's no way to un-ignore until another one of the Material is in the Contacts Panel
- illicit Cargo is also scooped, so pretty much every conceivable Commodity eventually has to enter the Ignore list in order not to run into trouble i.e. Bounty Hunting w/ Collectors in a RES/HighRES
--> but the contained Commodities might be valid Mining Targets for a Mining run sometime later
--> plus the next Pirate NPC going down might drop yet another type of Cargo not manually ignored yet - so the same problem arises again
(I found myself frantically trying to get rid of Illicit Cargo getting scooped over and over, eventually I resorted to ordering my NPC SLF to shoot the darn canisters under my belly with the Cargo Hatch closed - since I jettisoned them already and Authority could scan them & fine me any moment

)
IMHO the whole Ignore UI would work better like this :
- chosen from right Panel at anytime (no dependence on Contacts panel)
- Materials Page : general collecting ON/OFF (overrides individual Materials perferences)
- individual Materials : ignore YES/NO
- Elements Page : collecting ON/OFF (overrides individual Elements perferences)
- individual Elements : ignore YES/NO
- Cargo Page : general Cargo ignore ON/OFF
- Cargo/Material/Elements storage full : ignore for respective items are temporarily automatically switched to ON with notification
That way, the Player can set easy, overall restrictions (Materials/Elements/Cargo) and avoid any Collectors to waste time on these or shove unwanted stolen Cargo onboard.
At the same time, it also allows to finetune within Elements or Materials.
The Option to perform the same task on individual items via Contacts Panel can remain as it is right now, since it would likely still be useful for some Players or in certain situations.
On top, I'm frequently seeing the Contacts page shuffling wildly around every Second, especially when many Ships and other stuff is in the area and the list becomes quite dynamic.
Pinpointing the right item can quickly become a sheer mini-game of patience and luck then. Would be neat if there was an easy solution to that.