My eyes started hurting so I didn't read the past 8 or so posts, but um... A few posts up somebody suggested counting chips whenever somebody cracked a table, or a table was added to the event. Suppose you start with 3k in chips, well 9 handed if it gets down to 5 people before you break the table, there should be 27k in chips there.
Another thing, OP mentioned he had his suspicions about who could or couldn't be doing it. Well, put 2-3 of those at the same table, and when you break the table and you're over your expected amount, that narrows it down a little bit.
Also, if you break hourly/every two hours, you can recount then. I've played in a few of tournaments (where I'm from, they're ussually held at a restaurant with a lot of people who have a large community of common friends, all with an interest in poker, and the event will be held in a restaurant or something, that's been closed for the day because the owner wanted to have a tournament), so I know what the atmosphere is going to be like, players dealing to players, it makes sense.
But the following holds true:
1. Side games need to use different chips, period. I think you mentioned being in Ireland, but in the US at least you can get a decent little dinky chipset, 2 decks of cards, a dealer button, 5 dice, and a carrying case for $20. You can rent those out to have them pay for themselves to justify the cost. ($1 per player in a 9 handed cash game, you are 90% there after the set goes out twice.)
2. The chips need to be locked up when they're not in use. If you are worried about the integrity of the staff, you might try counting chips before and after the event. You catch one perp, they'll squeal. Especially once they realise their job is threatened.
**BEFORE DOING THIS, YOU SHOULD LOOK UP YOUR LOCAL LAW, OR SIMPLY ASK A LAW ENFORCEMENT OFFICIAL, IF SOMETHING LIKE THIS IS ILLEGAL. I DO NOT KNOW YOUR LOCAL LAWS, BUT THIS WOULD WORK WHERE I'M FROM**
3. You mentioned that where you are you're not legally allowed to search your patrons. Well, here is what I suggest. Set up a table on the inside of the door that all patrons must go through. You inform them that it's come to your attention that a regular at the tournament MAY be cheating, and that if they are going to play, they need to volunteerily open up their bag/empty their pockets. You are not forcibly searching them, however by having them turn their pockets inside out and letting you poke in their bag, you are assuring them a safer game.
Also, your perp(s) is(/are) going to get to the table, and find out what it's for, and refuse. Of course, there are hidden pockets in bags (my backpack the army issued me has one, and you'd think they'd want me to be able to hide as little from them as possible). Even a small amount of 1k chips can make a difference, especially later in the tournament.
You might just change out the larger denominations of chips, or switch their denominations around. If I were to be a dishonest person, and the tournement I frequented (and cheated at) used the same chips every week for their 1k/5k chips, I'd try and get my
hands on a few of those and try to add them to my stack on the down-low. They'd be in spot not likely to be checked when I went through your security table (tucked into my socks under my jeans, perhaps), and as I went to the restroom on breaks I'd move them to where they'd be easier to access (jacket/pants front pocket).
Well, if my 5k chip was worth 5k last week, and worth some random amount the next week, and I had to go through a security table (as weak as it is), I'm much less likely to grab a few 5k chips this week. Think about it. Preventative measures are just that.
Since you're doing this on the regular, you might increase the tournament fee a couple bucks each tournament (what's the difference between $33 and $35?), or skim a small amount off the prize pool, to buy multiple sets of chips, as well. I don't have custom chips (yet. Once I'm out of the service I'll have a room set aside for my weekly poker nights and have custom chips and maybe even a custom table, should my poker winnings be able to afford them, or should I be getting paid stupid good after my education), so I can't tell you how much they cost. But you take $40 more out of the prize pool (maybe first place will notice $7 less, second will notice $5, 3-4th will notice $4, 5-8th will notice $3, etc.) you'd be surprised how quick that adds up.
Anyway, that's enough wall of text crits for me tonight.
- Goat