[RC-Monster Mike]

Also, I doubt the broken trays described here actually broke during the described activities. A rolling truck won't likely brake the tray unless there is a big, heavy battery in it that is pretty loosely fixed and can slam back and forth into the tray walls. Most likely scenario would be that the trays broke the previous time out when the user "porked the landing on that big jump" or "nosed the big triple at 30mph", but didn't notice(or completely break) the broken tray. I haven't broken a tray in 2 years - I don't crash a lot, but I do crash - and sometime pretty spectacularly!
Getting a tray that fits the batteries is a good precautionary step. Cinching the velcro straps down tightly is also wise practice. A small pack in a big tray that is loosely held is a recipe for failure - there is a lot of inertia when a pound+ of mass is slammed into the tray end. Of course this isn't good for the battery, either. :)