Whilst it seems that there is some of sort of protest movement trying to get taxpayers to claim their private security cost as tax deductible, SARS has made it plain that this is not a legitimate deduction.
Sars warns against security deductions for tax
The South African Revenue Service (Sars) has warned taxpayers against applying for deductions for private household security as a form of protesting against crime.

Honest, non-suspecting taxpayers could, as a result, end up committing a crime themselves, Sars warned in a statement on Wednesday.

It said the caution "not to be misled by irresponsible tax advice" followed public calls by lobby groups advising people "incorrectly" on completing their returns "in a manner of protest".

However, the caution was described as "hysterical" by the National Civilian Safety and Security Action (Nacissa) lobby group, which accused Sars of trying to curb South Africans' right to apply for "reasonable" tax deductions.

"If hundreds of thousands of South Africans apply for tax deductions for safety and security expenses it is clearly something the government should take serious note of," said Nacissa spokesperson Conrad Beyers.

In a statement on Wednesday, Sars said the withholding of tax was a crime.

"The Income Tax Act does not allow for individuals to claim expenses for private household security from their taxable income for the last financial year.

"Any advice to the contrary has no legal basis. Sars will reject such claims from individual taxpayers," it said.
full story from M&G here
Of course, if you are operating a business from home, there may be some legitimate potential to make a claim on security costs as a business expense. (Be sure to check with your tax advisor on this).