Hiya! Yup it happens, just FYI for future ones can setup "beeper" on a switch and so long as it doesn't huck the battery (strap it down good) then can flick the switch to make at least the motors beep. For bigger quads I use a vifly v2 buzzer with it's own little battery pack so even if my main battery flies that thing goes into alarm mode in 30s if I don't find it and push the button and at that point it becomes hard to ignore (only downside being if stuck in someones tree, luckily it is smart enough to shut off at night but can get annoying no doubt... it's loud).
Regarding the battery.... it's not a major problem as long as it doesn't get punctured and doesn't get crazy hot or short out through something low resistance (allowing lots of current to flow and therefore lots of heat to be given off). I don't think rain water is low enough resistance to worry about it happening naturally but if someone mows the grass there ever they might be in for a surprise.