You can decline but ensure you make it quite clear when you are in hospital though.
I did Dom for a year once when the Dom midwife was on maternity leave and I was always welcomed with open arms and heaps of questions. It was actually pretty hard to get out of some homes but these were mostly first time mums. Experienced mums don't necessarily need the service as rule and I found are less likely to take aboard any advice as they have found their appropriate way to manage.
I understand that not all visiting midwives are created equal but if they check your baby bedding it is not because they are out to catch you out it is because it is their duty of care to ensure you are following SIDS recommendations. There is also a duty of care to ensure that you are well, that you have food, that you have support and that your home is generally a safe environment for everyone. You can imagine how it would be to ignore the fact that the baby was sleeping in a bassinette with a bumper and a mountain of soft toys only for it to die from SIDS.
I know some people feel offended, one of my DD's felt she was having her common sense questioned but after I explained why she asked what she did she felt better about it.
The questions with regards to weapons/drugs and pets are routine. Hospitals can not send out their staff into dangerous situations. I worked in Dom before this type of red tape was brought in and some of the places I went to were definitely extremely frightening.
The District Nurse service also has the same questionaire, it is routine and is not implying that they think you are dodgy.
Just remember, mention this before you leave hospital, save the Dom nurse from travelling for an hour only to find you are not home/will not open the door because there will be someone else who could really have benefited from that wasted time