There's live, and there's live. If you want to do a demo that's not basically faked up, you have to de-risk it to the umpteenth degree. There's a number of rules you follow for successful demonstrations. Here are mine:
1. If humanly possible, have all the necessary server fire-power you'll need on-stand. You don't want to rely on off-site equipment unless there's no other option (see point 3);
2. Show power is notoriously bad. Even when it works, the voltage isn't always stable, and you could well have equipment killed by voltage spikes. So put all your servers and key equipment on uninterruptable power supplies (UPSes)! Fully charge the UPSes beforehand, and test them. Get a good idea how long they'll last without mains power, so you know how quickly to shut down your stand kit if (who am I kidding?...when) power goes. On the show floor, put the UPSes on surge protectors;
3. Do everything from pre-loaded data on-site: if you're dependent upon Internet content, or off-site servers, I promise that your most important demo of the show will fail spectacularly;
4. If you can't avoid internet connection, never ever use site networking. Not only is expo network service larcenously expensive, it's usually dial-up slow, heavily contended, may be insecure, and is always highly unreliable. It's far better to get a load balancer/firewall, and plug a rack of cell network dongles into it - each from a different cell network, so that you have redundancy if one of them goes wobbly. You'll get broadband-equivalent speeds - especially if you've LTE available - in stark contrast to show networking. The staff on nearby stands will be crying with envy. (And there's nothing sweeter, when they're the competition!) Best of all, even if you throw the net dongles in the bin at the end of the expo, it'll still have cost you far less than buying from the organisers;
5. Hire a hotel suite, and set up the hardware there, before you move it to the show. Sort out the cabling and networking issues beforehand. Label up the wiring, so it's plug-and-play on the day. Practise the pitch and the demo, in the suite. This is particularly important if you've hired local demonstrators for the show! Get them to the point where a visitor will think they're getting it "canned", it's so smooth - and then, when you're challenged, say: "Go on then, you have a go." Trust me, this is a golden moment! And you'll have differentiated yourself from all the canned, faked demos around you, and created some belief in your product.
These last two points apply whether you're doing a canned demo or live:
6. Get your kit installed on the show floor as early as possible; if necessary, buy early access. Make sure you have your last-minute panics days from the "last minute", to give you time to get out to Best Buy or PC World to replace that broken network switch, the cable that got driven over by the fork-lift, or whatever;
7. Security! Think this through, end to end. Secure everything you can, every way you can. Have redundant kit if possible, and keep it off-site but near at hand. If stand kit goes missing - even just a vital cable - the commercial damage can be catastrophic. A new IPTV supplier (I'll spare their blushes) turned up to their first IBC, to great fanfares and acclaim for their rather innovative début product. I was working a stand that year, but wandered over on the last morning to take a look at this new marvel...to find a stand full of long faces. Some light-fingered oik had pocketed their one demo model! Don't make the same mistake...or you may as well have just spent your entire show budget on an exotic expenses-paid holiday for your favourite staff.
