oh my gosh! not the face!

infiltration and 1st turn charges. yes timmy, they CAN happen, and what you can do to avoid them.

Last night I played DONKEY. He played my all Light Infantry Guard list. I'm not sure why he didn't go get his Necron, or Chaos, or Orks out of his car, but I'm not sure he wanted to play me that bad. DONKEY refused to play the Sisters, so that left me with GK's, after he took the IG. I'll try to get the IG list put up sometime.

Spearhead Deployment, 4 counters on the board to claim. I got 1st turn. I took a corner with a hedge and wrecked rhino in the bottom left (center of my deployment, and a hill on the left center of the board. There was a power station in the center, (Cygnar Storm Research Station) a hill in the far left center of the board, on DONKEY's side, but not his deployment quarter. There was also a hill on my side in the far right hand side of the board, not in my deployment. Then there were trees back in DONKEY Deployment corner.

I was playing the DH list I've posted before. I had the Inq. Lord shooty retinue behind the hedge, with 2 rhinos up to the 12" from Center, and GK Psycannon squad between them, all of this towards the left center of the board. The IST's stood behind their rhinos, ready to get in. The GM and 10GK squad, were in their LRC, on the right center of the board at the 12" from center line.
So then DONKEY could set up wherever he wanted. DONKEY asked SandWyrm for help, and Sandwyrm explained the tactic of putting the Missile Launcher and Grenade launcher out front, then snaking the squad behind cover, and other squads, to have over 50% behind something to get cover saves.
DONKEY didn't deploy very well. This army ALL has light infantry. He could set up ANYwhere, as long as he was 18" away when in Line of Sight, and 12" away when hidden.
He was right at 18" away from the LRC, with 4 squads on the right side of the board. The Grandmaster and 10 GK's were gonna get to take some names.

I thought about calling the game. getting a 1st turn charge on 1/3 of the army means death. Especially when I know Shelia's going to pop up in turn 2 or 3, fry, and then snickety-snack her way through the 'safe' guys in the back who didn't get shot up by the Inq. Lord or psycannon GK's.

Get in the Van
When there's a big bus 'o nasty on the board, you don't want to take a 1st turn charge when you've got a shooty army. I'm not sure ANYONE wants to take a charge on 1st turn, before they move.
If you can infiltrate, deploy farther than your enemy can reach. For instance, a LRC can move 12", an plop things out 2" from the hatches. the bases give about another 2" if they're termies (which the GM is), and then there's a 6" charge. that's a threat range of 22". If you measure and deploy 23" from your opponent, and they somehow still hit your line, please call them out on miraculously moving FARTHER THAN THEY POSSIBLY CAN. c'mon, it's math. There are rules to the game for moving.

Aw Man, where'd he come from?
now if you happen to be the infiltrator, you can also use this information to your advantage.

One that many Imperials like to use (because I don't know that Chaos 'dex infiltrators very well anymore) is the Eversor asassin, he's got 6" move, and 12" charge, for an 18" threat range. Guy Smiley is one of the few Infiltrating units that Inquisition players get. When He infiltrates, measure the 18" to a juicy squad, and check your 12" hidden options.
If you've got 1st turn, 18" in the open isn't a horrible choice, but coming around a corner to charge from 12+" is better, in case your opponent steals the initiative. If you're 2nd, you definately want him hidden.
since with infiltrate you get to set up after all deployment, take the time to measure, and deploy carefully. Your opponent's going to know what's coming, and that's fine. That can sometimes misdirect attention from other dangerous aspects of your force.

We bring measuring tools for a Reason
finally, it's sound to be aware of distances in 40k. knowing how far your troops are away in deployment is a really good thing. Knowing how far your opponent can move and charge is good as well.
When your opponent gets the chance to measure something (in the proper phase, of course) pay attention. Measuring is telling you something. Use the knowledge, and plan accordingly.