I worked as a veterinary nurse at a cat-only clinic back in the states, so I'm well versed as to how difficult it can be to get blood samples from cats.
I do think many nurses and veterinarians do have a more difficult time with cats and aren't as great at restraining them. I know when I started a new job at a small animal clinic, they were extremely impressed with my cat restraint skills. I was able to teach them a new hold that made the cat more comfortable.
But!! Cats are still very difficult!! I've seen tons of incredibly sweet cats turn out to be monsters when it came to restraining them and sticking a needle in them. Or some just really, really, really, REALLY don't want to be poked and wiggle so much you can't keep them still enough to get a sample.
It also doesn't help that drawing blood on a cat is MUCH more difficult that drawing blood on a dog, even a dog that's the same size as a cat. Dogs' veins are larger which makes it easier.
Pretty much any veterinary nurse can draw blood on a dog. Not as many can successfully do so on cats consistently. That includes me. I got good at drawing blood from cats when I worked at the cat-only hospital but lost my touch when I moved to a new clinic where we saw mostly dogs. At least I'm still good at holding cats.
I know you say your cats would be fine if everyone is gentle, but you can't really know what exactly they'll be like in the back on their own surrounded by people they don't know who they think are trying to hurt them. I'm not trying to say you don't know your animal at all or trying to be rude in anyway...but just being honest. Many people think their pets will act fine but it doesn't turn out that way...and it isn't necessarily the staff's fault. Sometimes animals freak out when they're scared. It happens and it's okay. Sometimes some anesthesia is much better for them so they don't have to be poked too many times and the process is over quickly. It's just unfortunate that anesthesia is so expensive.
Did the vet say if they were aggressive? Perhaps they were just too wiggly? I know that being too wiggly was the main reason we had to anesthetize cats in order to get a sample.
madiera: I hated holding cats for blood pressure tests! Did the vet put the cuff on one of the back legs? It was always so difficult because cats don't like their feet/legs touched, or being held down, or the squeezing sensation...plus you had to keep them so still. I had to do it quite frequently because the vet I worked for found hypertension to be more common in cats than originally thought. It was good in the end though. Just a simple pill a day greatly improved the quality of many cats' lives.
