The opening should be used to get you to a middle game YOU want to play.
Taking a move from an opening DB without knowing why it was played and
what is it preventing or threatening is dodgy.
If you get involved in a tactical line then be very careful about the
move that leaves the DB. DB's are main line moves, they do not show
all (or any) of the traps (some of which can be very deep and do not need
to end in mate or a win of the Queen - there is such a thing as a postional opening trap).
These bases are made up from GM games. They won't play opening tricks v
each other in the opening, but at the lower level these things work.
On here the Blackburne Shilling Gambit has claimed 104 victims.
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nd4 4. Nxe5 Qg5 5. Nxf7 Qxg2 6. Rf1 Qxe4+
The Shilling Trap is not even what I would call a heavy tactcial line.
I'm just using it as an example of how moves no GM woul play v another
GM win at a weaker level,
So blindly taking moves from a DB made up of GM games is OK provided
the other lad is doing the same.
In short you are both making moves which will make sense in the coming
But the chances are you won't see the middle game position the opening
moves in the DB were designed for.
You will instead be looking at a pawn or piece sac, a premature attack,
a basic one move threat or even a sensible developing move that has
been deemed too passive at GM level so therfore unplayed.