Now that seems entirely plausible. My tank is held on like that, and I've wondered a couple of times in passing if it was enough. Did the reports in other forums say what kind of straps should be used? Seems like an easy preventable fix.
No, most of the discussion was how to replace the tanks, what model number, the cost of replacement, whether the failures were manufacturing defects, warranty coverage, how to get the tanks out, etc. Although I didn't see any posts directly addressing adding straps as a preventive measure, the difficulty of replacement indicates that because the tanks were installed during manufacture, a retrofit of the straps would be difficult.
After reviewing the posts again, it seems like that problem is also with older rigs, not just within the last couple of years. There is one member with a 2006 model that has had multiple tank failures with both his black and gray tanks.
The discussion is on the Montana Owners Club forum under "Montana Problems, Problem Solving & Technical Help". You can't see the forums unless you join the site.