Ha, Planking, has it's own definition for ice fisherman   Just think of what the social media world would think of our definition compared to the craze of a few years back 
I'm with Slab.  Usually, literally when it comes to planking.  Same thing, 2x8 or 2x10  make sure you put enough of it on shore so it doesn't slip out from under you.  And if it takes more than a 10' we're done.  Also make sure you are going on from the side of the lake the wind is blowing into so if the ice moves, it moves towards the shore.  And I won't do it if I know the water is deep enough to be a problem beyond wet legs up to your knees or so.   Carry extra clothes too, just to avoid a wet leg on the drive home.
I've left them without problems, except if you go home and someone has used your plank to get out you can strand them which isn't good.  But losing a $10 hunk of wood is no big deal in the larger scheme of things.

Not seeing the poll Nate, I'm in with Joel. 
As for ice, was with Joel yest. Like he said, we didn't see anything less than 5" but as usual, that isn't a promise for EVERYWHERE out there.  Weird stuff still happens. Every lake has places where current can prevent good ice formation.  But anywhere that is popular for fishing out there has people out on it and no one coming back saying it's thin or sketchy. 

Not to disparage the fellows business, but last Friday we were fishing a bay and two young fellows came sliding out in their sneakers said "how much is is there" and "are you guys catching any fish"  When basically ignored by the group of us who were trying to stay far apart on 3" of ice they announced that they worked for said previously mention pro shop and just came down to get a report. 
There was open water 25 yards away and numerous areas with 1.5 or less and they were telling people it was safe because people were on it. 
I understand they need to sell bait and tackle and make money.  But a lake like Indian with so many channels, cuts, canals, bays etc. will be highly variable.  To say the lake is 5" or "safe" is misleading and dangerous. 
As stated before, go out and check your own ice.  Or wait another 10 days until everyone who does the checking has been out and follow their tracks. 
We happened to spend quite a bit of money in that shop that morning, but only asked if anyone was getting out on the ice and then drove around until we found ice we felt was safe.  Apparently, most shops aren't going to tell you not to go out, any more than they will tell you not to come by if the fishing has been awful for the last 3 weeks.  Before we all had computers, we would drive down to the lake and spud and check, occasionally literally getting our feet wet. It's still the only way to be certain.

I also carry along my throwable cushion from my boat.  Could help someone or myself if you go in, and makes for extra padding on my seat or a nice kneeling cushion when hole hopping.  Also make sure you have some type of lanyard/ wrist strap for your spud bar, there are lots of them on lake bottoms

If you don't find one used, go see Mark in Ravenna, he's a sponsor for the panfish series and host shop for the championship.  He had the Eskimo Quick Fish 3 in stock for $150 if you told him you were an IFO member.  Lots of others too and only about 20 mins. from you.

Thanks G, looks like the long rods or dock will have to suffice.

Safe is always relative, no one seems to be advocating others taking risks.  Safe for me is 4" and a type 1 life jacket on, picks, rope etc.  and checking areas that aren't over my head if I do go in.  Plenty of excitement over a long awaited cold snap.  But with the reports coming in, some areas will be 4+ by Friday at the latest.  By the end of next week, most inland should be 5" plus and okay for foot travel.  Probably safer than fishing from the boat has been with 36 degree water temps.