To be furious with workmen?

[Moocherbot]

My mother (mid 70s) had workmen in from Carpetright laying vinyl. 3 of them turned up. They told her they had run out of silicon and made her go out to a DIY shop to buy more, leaving them alone in the house.
She has told me this now and is clearly feeling guilty that she didn't put a stop to it at the time, so she's backtracking and telling me maybe this is normal.
Normal to get an elderly woman to go out to buy supplies (which she knows nothing about) that you ought to have brought, when there are 3 of you, and leaving you alone in her house?
I think it's outrageous, I want to complain about it, but she doesn't want to. I really want her to understand that you can say no to people or make an excuse but it's so hard to get through to her.
Any tips or advice please?

Yes, I did read it and respond to it....

Did you read this update from the OP?

Yes, I did read it and respond to it. I'm not sure what you point is.

@Marynary - what about the point that, even if nothing is missing, they may have been casing the place for a later burglary? Or that, if not reported this time, they may do this again, to a really vulnerable person?

If this were my mum - aged 82, physically frail, but mentally still all there - I would report it, if she wouldn't - for her protection and for the protection of anyone else they might do this to in the future.

As I said earlier - I cannot think of any legitimate reason why workmen would insist on the homeowner going out and leaving them alone in the home - I don't think anyone has. They were up to something.

Furthermore, if they have done this once, they are going to have done it more than once. And they will do it again and again until someone reports them, and they get stopped.