it has happend to me twice that Lightroom exports also the deleted photos... I haven't noticed it and handed over to my clients also the bunch of unwanted photos. I mean, pretty annoing. Anyone has an idea?
Do you really mean "deleted photos" or do you mean "rejected photos"? It's difficult to see how genuinely deleted photos could remain available for export, whereas of course rejected photos most definitely do remain available for export.
If you mean "rejected" photos then you can filter your album/collection to hide all such "rejected" photos so that they won't be included in your selection for export.