The slippery slope - fallacy or as I suggest not always.

Ok so this is trotted out all the time in respect of gun laws, marriage........

link to slippery slope study

An interesting read and here is the conclusion:

VIII. CONCLUSION
Sandra Starr, vice chairwoman of the Princeton Regional Health Commission
. . ., said there is no "slippery slope" toward a total ban on smoking in
public places. "The commission's overriding concern," she said, "is access
to the machines by minors."
- New York Times,. Sept. 5, 1993, § I, at 52.

Last month, the Princeton Regional Health Commission took a bold step
to protect its citizens by enacting a ban on smoking in all public places of
accommodation, including restaurants and taverns.... In doing so, Princeton
has paved the way for other municipalities to institute similar bans
- The Record (Bergen County), July 12, 2000, at L7.

Let me return to the question with which this article began: When
should you oppose one decision A, which you don't much mind on its
own, because of a concern that it might later lead others to enact another
decision B, which you strongly oppose?

One possible answer is "never." You should focus, the argument
would go, on one decision at a time. If you like it on its own terms,
vote for it; if you don't, oppose it; but don't worry about the slippery
slope. And in the standard first-order approximation of human behavior,
where people are perfectly informed, have firm, well-developed
opinions, and have single-peaked preferences, slippery slopes are indeed
unlikely. People decide whether they prefer o, A, or B, and the
majority's preferences become law without much risk that one decision
will somehow trigger another.
Likewise, in such a world, law has no expressive effect on people's
attitudes, people's decisions are context-independent, no one is ignorant,
rationally or not, and people make decisions based on thorough
analysis rather than on heuristics. Policy decisions in that world end
up being easier to make and to analyze.
But as behavioral economists, norms theorists, and others have
pointed out, that is not the world we live in, even if it is sometimes a
useful first-order approximation. The real world is more complex, and
this complexity makes possible slippery slopes and their close relative,
path dependence. We can't just dismiss slippery slope arguments as
illogical or paranoid, 330 though we can't uncritically accept them, either.
330 See supra note 6.

1136 [Vol. 116:1026
HeinOnline -- 116 Harv. L. Rev. 1136 2002-2003
THE MECHANISMS OF THE SLIPPERY SLOPE
The slippery slope is in some ways a helpful metaphor, but as with
many metaphors, it starts by enriching our vision and ends by clouding
it.331 We need to go beyond the metaphor and examine the specific
mechanisms that cause the phenomenon that the metaphor describes
- mechanisms that connect to the nature of our political institutions,
our judicial process, and possibly even human reasoning. These
mechanisms and their effects deserve further study, even if paying attention
to them will make policy analysis more complex. So long as
our support of one political or legal decision today can lead to other
results tomorrow, wise judges, legislators, opinion leaders, interest
group organizers, and citizens have to take these mechanisms into account.

So based on the above there IS a slippery slope - but we don't always slip

I will attempt to show that CCTV was indeed a slippery slope we are/have sliding/slid down at breakneck speed at least here in the UK.

From an article i found back in 2004

In 1990, just three towns had systems. Now some 500 do, after a decade in which more than £250 million ($460 million) of public money was funneled into CCTV systems.

BBC article from 2009: link

The City of London [borough] has 619 cameras, but a population of only 9,000. This represents 68.7 cameras per 1,000 people.

The borough of Wandsworth has the highest number of CCTV cameras in London, with just under four cameras per 1,000 people. Its total number of cameras - 1,113 - is more than the police departments of Boston [USA], Johannesburg and Dublin City Council combined.

from the Telegraph in 2013 link

The British Security Industry Authority (BSIA) estimated there are up to 5.9 million closed-circuit television cameras in the country, including 750,000 in “sensitive locations” such as schools, hospitals and care homes.
The survey’s maximum estimate works out at one for every 11 people in the UK, although the BSIA said the most likely figure was 4.9 million cameras in total, or one for every 14 people.
Both projections were higher than previous estimates which ranged between 1.5 million and four million.
Simon Adcock, of the BSIA, said: “This study represents the most comprehensive and up to date study undertaken into the number of CCTV cameras in use in the UK.
“Because there is no single reliable source of data no number can ever be held as truly accurate however the middle of our range suggests that there are around five million cameras.”

So I would suggest that those people who said the first cameras installed were the top of a slippery slope were correct - they are indeed everywhere now.