Would you consider tricking a person with poor literacy skills into signing a contract that gives them your house a moral thing to do? Why is tricking somebody into giving you full access to their computer any different? Also, much like legal contracts can still trick the literate, these installers can trick even technically proficient users who weren't expecting to suddenly have to engage in a battle of wits with their computer.
I have seen installers with right bottom for OK, and left to Cancel install, as is is standard. However, a few steps into the installation, a toolbar question came up where OK meant install toolbar and Cancle meaning not installing toolbar but continue install. Bascially, left button Cancel went from aborting the install to continue the install through a sleight of hand trick (deception). Since its done for economical gain, its fraud - As clear case as it can get.
Fraud: intentional deception made for personal gain or to damage another individual.²
¹: 3 year binding agreement with first month free.
If you want, I can list several similar crimes like salting the mine², the Romance scam², or the classic Nigerian scam. Each too allows the victim to opt out, each are equally fraudulent behavior, and equally illegal. The law do not require that the criminal has lied, only that deception has happened.
Giving the victim a chance to opt out does not give scammers a "get out of jail card". If it did, that would be the first thing any caught scam artist would say.
¹ http://www.actionfraud.police.uk/fraud-az-invoice-scams
² https://en.wikipedia.org/wiki/Salting_%28confidence_trick%29
Smashing 'next' in an installer should do the right thing: it should install the things you most likely need in the app you downloaded, in the place that makes the most sense on your system, etc. In almost no cases is the right thing installing some random ass toolbar.
There is a clear reason "I Agree" is pre-checked. Educating users is a band-aid, treating the symptom and not the cause. The cause is scummy companies like InstallMonetizer, and hopefully people like PG/YC will come to see how it hurts their brand, no matter how they think reality differs from peoples impressions of such companies.