By themselves. no. Their purpose is partly redundant. They were originally intended as a marker for friendly mines.
A mine marker excused you if a friendly drove over a mine you place them by. And you could be sneaky and use them to make enemy believe mines exist in an area, and thus would avoid them.
However, since about an update or two ago, the devs made the skull and crossbows appear automatically (As opposed to using the shortcut key to put on notifications), so their use has diminished somewhat.
Although for the life of me, I can't understand why people still run into skull and crossbow areas and kill themselves.
One would think the convention crossed beyond video games.
