"Choping" is Singapore English slang for reserving something well in advance, i.e. a place in school for your child, etc. That is, it is one of the actions involved in the unraveling of markets, the process by which transactions are arranged increasingly far in advance of when they will be carried out. Sometimes this has been a cause of market failures that lead to new market designs, with a prominent example being medical labor markets.
In some cases, the unraveling of a market has caused serious inefficiencies, as when college football bowl games used to be decided before the end of the regular season (which made it harder to arrange the kind of championship games that draw high television viewership), or when gastroenterologists used to be hired long before they finished their internal medicine residencies (which caused the national market to collapse into lots of regional markets). But, in most unraveled markets, data are lacking to directly determine if a particular set of market arrangments and timing are inefficient.
Tyler Cowen at MR has a (characteristically) very interesting post on choping at Singapore food courts, where patrons reserve seats by placing tissue papers on them, and then go to stand in line to get their food. He suggests (maybe just to be contrarian) that this is efficient. As one of the comments to his post points out, this would be the case in a model in which having to look for a seat once you have your food is incomparably more costly than any other outcome. Of course it is easy to see how (with different parameters) reserving seats in advance could be inefficient (although still an equilibrium). E.g. if it takes 15 minutes to get your food, and 15 minutes to eat it, then each chair could serve four people in an hour if people looked for a chair after getting their food, but only two people per hour if people reserve a chair before getting on line.
The discussion of all this in the Singapore press is satisfyingly nuanced. After a demonstration against choping by some students (Wiping out bad habit of 'choping' seats with tissue pack), the Straits Times has a story (Is this rude?) that explains both points of view.
On the one hand:
"But many people reckon there is nothing rude about reserving one's spot with a packet of tissue paper. Indeed, Mr Wong, who arrived in Singapore last month, said: 'It is a practical and creative way to reserve seats instead of standing around with a tray of food turning cold.' "
On the other:
"Tissue 'choping' seems to be uniquely Singaporean. Housewife Ivy Ong-Wood, in her late 30s, a Malaysian now living in Hong Kong, told LifeStyle: 'At the tea cafes or cha chan tengs in Hong Kong, people queue outside and are told where to sit. In Malaysia, there is no problem getting seats at the food centres.' "
Whatever the truth of the matter, this will not be an easy equilibrium to displace. The story notes: "It is so pervasive that companies even have tissue packs specially made with the word 'chope' for marketing purposes. "