The company I work for does something similar. We have 1 main site “website.com” and we host hundreds of landing pages on “web.website.com” that’s masked as “website.com/web”
From what you described, I see no reason why you would get a penalty,click here and scroll to the bottom and you’ll see common ways people try and trick Google
Guys… do you check domain availability ?
What seo tools do you use to promote your site and rank it higher?
I came across a good thing which helps to check websites traffic stats Website Traffic Checker: Check Website Traffic Stats in One Click ᐈ .
Do you know anything like this?