Possibly, but they'll get caught on camera if the do. If it's any comfort, I'm abotu 6 foot could easily reach 8 ft. If someone really wants to disrupt a camera they can do. They could shoot it from afar with an air rifle, spray paint the lens, wear balaclava's etc. Tht's why most have multiple cameras and that's why no 1 method is 100% effective and why many recommend fitting a burglar alarm before a camera - it's all about deterrence as much as detection. The harder your property is to get into, the more likely the burglar will move elsewhere to an easier target.
The other alternative to get them a little higher is mount the cameras where the lights are and get the installer or an electrician to move the lights higher.One issue with fllodolights is the lower they're mounted the more they have to point outwards to cover an area and the more it dazzles neighbours from seeing what's going on. The best fllodlight is one mounted high and pointing almost straight down as it lights the area but doesn't dazzle observers. There was a burglary at the back of me where the householder had a floodlight and suffered exactly that problem. A neighbour saw them but couldn't see what was going on because the floodlight was shining outwards and dazzling them. So they did nothing thining everything was normal and it was just the sons and his friends being noisy, and it later turned out it was a burglarly.