Not to point any fingers at any particular company, however, there have been reported strange cases of “being too late” to register a domain name. I don’t know if you had this experience of checking a particular domain name, and that same name was registered later that day by someone else? There are two ways of preventing that.
1. Buy the domain name right there and then.
2. Brainstorm a set of domains on a service you can trust.
This part is a bit tricky. You either check with the source what they are doing with the lookups, or use someone who claims not to track or monitor lookups. That’s why we built our website checker where you can check domain availability. We wanted a secure unmonitored domain lookup tool where we knew we could check domains, and not be afraid of being late. We were sometimes brainstorming on a Friday night with a couple of beers. You probably did this too… Domainers hanging out, you get a cool idea or a name, and you want to check it right away. So we also built an iPhone app that does just that. app.whons.com (discontinued). Easy for me to say, having an awesome engineering team, and the resource (since some of those services we built in 2006).
However, we wanted to make this easy for anyone. So now you can either use one of the services and apps. Or you could use our domain availability API and build any kind of service with additional functionality. If you are not a developer and need someone to build a tool around our API, my assumption is it wouldn’t cost you too much to get someone on Upwork. The advantage of this is you could have it custom built with suggestions, many TLD’s, etc. You have to figure that one out on your own, you have us to worry about the API part. Depending on the number of queries you make, it might solve your problem for free.
Thing is, there is no way you can prove to the company that you were looking for a domain name that was later registered. You are in no way reserving a domain just by looking at it, or favoriting it in your notes. You have to secure that name for at least a year and be done with it.