It is, however, fixable by companies having common sense when they create such schemes.

I don't understand anyone who makes economic arguments here about the value of the particular certs or points or whether they are profitable. Over the years, in the US (this doesn't happen in Australia, fwiw), I've visited places such as CompUSA and Circuit City and bought mice, CD-RW media, RAM, etc, for nothing (after rebate). Now, if I go and buy something for $15 with a $15 rebate, is the company making money? No. Do they have the right to refuse my rebate because they were too generous? No. They limit these offers in the way they choose to (1 per person, 2 per household, or whatever) because it's a marketing scheme to get us in the door (or in the web site). They can fully expect that if they offer me something useful for nothing and I can get 2 per household, I'll buy 2.

Anyone with the slightest sense who puts a web promotion together should have set whatever limits they want on it and expect some people to take the maximum, just as bricks and mortar outlets do.