Getting mugged is always a possibility. Its happened to me and like half my family. But, certain id is irreplaceable if lost. In my province after they switched health card styles they made mandatory expiration dates, where my current one doesn't expire. I'd like to hold on to that. Is there a good method that anyone uses that is convenient for hiding things a theif wouldn't suspect. I'll always carry a wallet, as It'd be annoying to keep going in the secret compartment. But, for certain ids you don't need them that often anyways.
Put the card in an unused pocket and then sew the pocket shut. Carry a sewing ripper (http://www.sz-wholesale.com/uploadFiles/051215164945s.JPG) around in case you ever need to bust it out. It'll also help you defend yourself if you're ever in a "street situation" again.
What about those 'hidden' pouches? Like the ones that appear on airline magazines for travellers to keep money and such.
Where do you live that you get mugged??? Carry your ID in an ankle holder, and carry a dummy wallet with like $10. Keep your money on a money clip in your sock.
Or do what I do which is never carry much money in the first place - if I got mugged they'd get a pile of loyalty cards from various stores, a card I could have cancelled in 5 mins as I have 24hr banking, so by the time they'd reached the end of the street I'd have cancelled it. My 'phone is as cheap as I can get, mainly because I don't need to GPS where I live, eBay, Google or find the nearest Clothes Shop / Restaurant / Garage etc. Seriously, we all carry far too many interesting items. Even my laptop is shit. I own a nice iMac at home and a rubbish old iBook I use on the road so if it gets stolen I am never going to really care that much, insurance will deal with it. I never keep any important data on the laptop that isn't backed up at home. Not saying I wouldn't be pissed off if I got mugged, but everything can be replaced and I don't really need to walk about like a jangling shop front for some ned to feel is a smash and grab opportunity!