You don't say what this "facility" is - e.g., a public sports hall, or a private gymnasium in a school or a factory sports-&-social club - but I don't think it's anything more than to be expected.
The only employees who should be able to read the information are those administering the matches; but it is normal practice to sign in whenever visiting anywhere closed to the public.
If you are using a private gymnasium and quite possibly a public sports-centre you might be signing in as a "temporary" or "day" member of its owning organisation, so you are covered by its insurance. You are using someone else's property and they do need know who is there!
I would not worry about it!
As for what people can find out about you for their purposes; they are far more likely to do so, and find far about you, via social-media sites, Internet browsing and things like supermarket "loyalty cards". That's how Google, Facebook et al make their vast profits!
