Is this cruel to these cats?

[CatLitterTray]

I have visited a client today in a professional capacity. She has 3 indoor cats and 3 litter trays, each of which was full to the brim with cat poo. The whole house smelt horribly of cat urine.
There is a social worker involved, who I have reported this to. He says that he will ask the client's carers to remind the client to change the cat litter trays more regularly. The carers call every other day.
My question is that do you think that this is cruel to these cats? They are clean animals by nature and I feel that it is not fair on them if the cat litter trays are not emptied.
If the social worker does not manage to improve this situation, should I be reporting it anonymously to the RSPCA?
I would appreciate your views on this.

Personally I think you should at least get advice from the RSPCA.

Yes, it is cruel, and, yes, I would report.

Yes it's cruel. Yes it's filthy. Yes report to the RSPCA.

Regrettably YABU if you think a social worker would give two hoots about the norms of cleanliness.

Why have you also posted in Chat without even acknowledging replies here?

Apologies. Was just trying to get as wide a variety of opinions as possible.

Yes it’s grim, cats like clean trays. Poor cats.

Yes it's cruel, very classic animal hording behaviour. You might as well report it