Just had a tree surgeon at my mother's door, wanting to cut back a tree he saw in the garden. Luckily I was there and told him no thanks, but my mother said to me if it had just been her there, she would have said yes (and I fear would not have agreed the price first).
I don't think the tree in question really needed trimming, it had been done fairly recently.
Most weekdays I won't be there though. I printed some business cards with my name and number and told my mother to give any such people my card, but I fear she will forget and agree to overpriced jobs.