It is "safe". Our amps are protected from load faults or opens. However, since this is pushing the amp beyond its normal rating, it is POSSIBLE (although rare) to encounter overcurrent limiting on loud peaks, which sounds like harsh clipping. We haven't heard anyone actually complain however - speaker impedance tends to rise somewhat when pushing the power hard enough to reach this limit. Normally, the amp gently reduces power when pushed too hard for too long. If this peak clipping were to happen anyway, the trick would be to lower the Master by degrees until it clears up, which keeps the peak currents within normal range.