I'm travelling soon with cabin luggage only and I was wondering if I can take a disposable safety razor with me?
This page says it's OK, but it also says it's OK to take small scissors and I've definitely seen them confiscated.
Depends on the security measures of your departure airport.
All types of razor are prohibited.
Therefore, passengers should not have any sharp objects with them or in their hand-carried baggage (for example pocket knives, nail files, box cutters, razors, scissors, corkscrews, any sharp/pointed objects, etc.)
Plastic moulded razors are allowed, but razors that can be opened and razors with changeable blades are prohibited. I assume disposable razor = plastic moulded razor.
Razors that have the blade set into a plastic moulding are allowed, but razors that can be opened and the razor blade removed are prohibited
Disposable Razors (including razor with removable razor blades/catridges) are permitted. I believe the scissors you mentioned have length > than 4 inches, that's why it was confiscated.
Scissors - metal with pointed tips and blades shorter than four inches are permitted. Razor-Type Blades - such as box cutters, utility knives, and safety razor blades are not permitted. (disposable razors and their cartridges are permitted)
My advice is to check the security section of your departure airport's website.