Rather than crawling I maybe should have said swarming, its only when you see hundreds of them you realise how bad they had got, hidden away as they usually are in the substrate.
Since I mostly have sand in my tanks another thing I do is scoop a net through the sand getting a net full of sand and snails, then I swish the net in the water allowing the sand to fall back into the tank (dont do this near your filters intake) until I am left with almost no sand and just a bunch of MTS to dispose of. Very satisfying and the fish have a field day going over the freshly turned sand picking up tasty morsels.
I dont think napalm could even kill MTS, so most of the time I maintain a running battle with them since I cant use any poisons to kill the MTS as this would also kill my shrimp and wanted snails like nerites and notopala.
If using any commercial snail traps watch out for the fish, my not so bright endlers and guppies got themselves stuck in the trap and so did some of my shrimp, also I found the commercial traps didn't work so well for MTS so I made my own.