They should be using cable tie guns set to the right tension. They usually come with a sheet that tells you which tension setting to use based on cable tie mode

They should be using cable tie guns set to the right tension. They usually come with a sheet that tells you which tension setting to use based on cable tie model. If you are doing the same installs each time, it's a better idea to use a gun set to the right tension to avoid damaging the internals. The guns also cut off the extra bit too so it's a one shot action rather than pulling it through and then finding clippers. If this is IT, I used this hook and loop tape that you would came on large spools that you cut to length. You always got the exact length of tape you needed and there were never any parts to get caught. It was also reusable which was nice when you had to add an extra cable to the bundle.