Always buy water proof camera case or you will have to say good bye to the camera. While tackling streams when going up and coming down, all of us had somehow grounded the cameras, just in case if some one will fall in the water, at least camera is not damaged.
While walking on edges, always put your foot on the stones or boulders. Never rely on lahar; if you will, for sure you will fall. Piles of Lahar all along the track are soft and can not hold your weight. Also do not try to get support from Lahar walls while tackling boulders, it may trigger land slide.
Keep in mind that during rainy reason one can easily get stranded on Mt. Pinatubo trek. In the afternoon, streams on the trek starts overflowing and few become really a challenge to cross. So you can easily imagine what will happen if it starts raining....
Always carry a pair of hiking sticks with you. One of my companions had the sticks with him and he was a blessing for all of us when tour guide was just a spectator. Right in the middle of furious streams, he pegged his sticks and stabilise his feet and we then cross by putting our weight on those sticks.
Avoid passing the secondary routes going to Pampanga lest you get stuck during the rainy season. Just pass through the main roads. Since the spillways and waterways have been filled by lahar, it is quicker for the roads to get flooded. Check out or listen for updates on the news about weather condition.
Paskuhan Village, San Fernando Pampanga, 2000, Philippines