tamper-proof screws aren't
Not sure I can blame them for using philips screws. There are various screwheads around that are claimed to be tamperproof, but really they're just mildly inconvenient.
Many of them have drivers available in a kit from your nearest poundshop (where available) and those that don't can usually be defeated by hitting a cheap chinesium screwdriver so it moulds itself to the screwhead.
In short, they're worthless : tamperable by anyone over the age of 2 and most certainly by someone with an inclination towards overcoming locks.