This is done in many countries, John. You will find, especially in France and Germany, roulette chips is several denominations with all having several colors, along with markings (stripes or whatever) to seperate them from eachother. Where an American table is only seven or eight up, a European table can have as many as fourteen players. Infact, many of the games are played with each player using the same 5f or 5DM chip, and they're able to keep track as to who bet what, where. Their table pesonnel consists of more than two, of course.

As far as detection of chips being removed from the gaming area, or the builing is concerned, a special device is added to each chip during the manufacturing process, and even if cancealed, can be dectected when passing through an electo-magnetic gate. Surveilance systems such as vidio cameras and recorders can also trigger alarms to help floor personnel in preventing these chips from leaving the casino. This has been gong on for many years in several European casinos -- but the chips still get out.
John Benedict