I had an outdoor gig recently and I used my Berg 2x12 and my Tone Hammer 500 head. The wind kicked up at some point and I was seriously concerned it was going to blow my little 4# amp head right off the cab. That was definitely a first! Has this ever been a problem for anyone else? I'm wondering if anyone velcros their amps to your cabinets, which I'm considering.
There are several threads on here about using non-slip matting or pads to stop lightweight heads drifting off cabs.
You are certainly correct about that, after the winds died down the rain started intermittently and that was a much bigger problem!
In that case, I guess the tiny amp would be advantageous... you can just shove it in the inside pocket of your jacket and tend to the other gear.
Old bike innertube, cut to length, tied in knot. Good for carrying my rig the short way into the band's rehearsal space.
Swap to a SVT head? Unless you play in costal states prone to direct hits from hurricanes, it should take care of the problem. (And yes, that was intended as hyperbole.)
Even without wind, lightweight heads can move due to vibration of the cabinet. But all the aforementioned solutions will prevent that problem. If you have a very lightweight cab with a tall profile like your 2x12 with a head on top there may be stability issues. I have a GR Bass 212 Slim cabinet (28lbs) that I used with a Mesa TT-800 (7lbs) which sounds great but is top heavy and tipsy. When I use my Quilter BB-800 (3.5lbs and smaller) with shelf liner then everything is stable. Never had to worry about such things with the heavier cabs and amps.
I use a computer mouse pad for my Mesa D800. It keeps it from vibrating round on top of the cab when playing loud. Its never really been an issue but I was worried about wind in particular I always have some tape handy when I play gigs