Will strapping salsa anything cages on my suspension fork damage it? Will strapping salsa anything cages on my suspension fork damage it?  I'm considering bikepacking, and don't have a rigid fork on the bike I would like to use. 

I would likely be carrying something of moderate weight like a couple litres of water on the front of the bike. I won't be using panniers as I would like to keep the weight mostly centered and plan on quite a bit of off road riding.

Is it generally safe to use something like the salsa anything cage (or big bottle cages) strapped to my fork?  Could this damage the fork, more than just messing up the paint a bit?  

Likely mounted like this, with intertubes protecting fork, and hose clamps holding cages:

Source http://www.bikepacking.com/plog/bikepacking-the-appalachian-trail/
Jeremy at Cleaveland Mountaineering has a similar product to the anything cage and a shows a regular suspension fork as one of its uses.
http://cleavelandmountaineering.blogspot.co.uk/p/everything-bags.html

He also has a degree in mechanical engineering, so if there were a problem i'm pretty sure he wouldn't be recommending it.

From my own perspective, the vast majority of force the load is going to apply to the fork will be vertical and simply cause the lower leg to slide up and down the upper.
Fork lowers are also by nature pretty robust as they have to resist the twisting forces applied under braking etc.