In the abstract for the article Forecasting Etna eruptions by real-time observation of volcanic gas composition (Aiuppa et al. 2007), the authors assert that real time monitoring of volcanic volatiles, such as $\ce{H2O}$, $\ce{CO2}$ and $\ce{SO2}$ and ratios thereof, could be a potential tool for volcanic eruption prediction, as exemplified by their modelling of Mt. Etna volcanic volatile geochemistry.
However, at the time of the article, according to the authors,
It is generally accepted, but not experimentally proven, that a quantitative prediction of volcanic eruptions is possible from the evaluation of volcanic gas data.
Has there been experimental proof of the effectiveness of real time monitoring of volcanic volatiles in volcanic eruption prediction?