Having a website on the internet brings its downsides as well as its benefits. Rarely does a week go by without me receiving one of the dreaded emails saying that my site is broken or needs updating and particularly that my site is not optimised for keywords. Sometimes the website is mentioned in the email but frequently it is not which, if I could be bothered, would leave me with the question of which website are they talking about? I have several.
If it is obvious which website they are talking about I may take a quick look down the list of items they are talking about and usually one of the items is immediately verifiable to be false which tells me that these people are scammers who send the same standard email out to multiple website owners in the hope that someone will 'bite' and employ them to rebuild their website.
I have had it happen where I've been contacted by a rival web design agency asking if they can have access to the code so that they can introduce their own code onto a site that I have built for a client which places me in an awkward position with regard to my client. Having checked with my client I reluctantly allowed this to happen, after explaining that I would no longer be able to make changes for him as it would overwrite whatever the other web design team were doing. About 6 months later the client came back to me and said that the other web design agency was a disappointment and would I put his site back to the way it was before they got involved (which I did).
There is no easy way to stop this from happening. I can stop robots from filling in your contact form but I cannot stop people from doing so and legitimate companies, as well as scammers, can complete your contact form and send you a message. So how do you know if your website is OK or if it is in some sense broken?