Craftmaster there is a significant difference between lithium cells / batteries used in hobby application and those in consumer electronic devices such as laptop computers, mobile phones, etc. Those in consumer electronics are designed and tested with overcharge protections and also protections against forced discharge. Unfortunately many of those sold by hobby shops lack all of those protections, which is why you have to charge them outside or in a clay flowerpot as you demonstrate.
Bare metallic lithium will certainly react to water. A lithium ion battery will not as there is no metallic lithium. That applies to lithium polymer, lithium iron phospate as well, they don't contain metallic lithium and won't react to water.
As I mentioned in a previous post every incident involving lithium batteries that I've seen reported has been as a result of non-compliance with the correct packing method for cargo shipments, damage to the battery due to improper handling, or in a number of cases conterfeit batteries that had not met the UN test criteria. There have been no incidents where the batteries were prepared in accordance with the regulations.