The risk of non-payment goes up with an investment property vs. a primary or second home. Therefore, lenders assess additional fees at closing to compensate for this increased risk.
A couple of comments: First, it is a matter of the borrower's INTENT at the time of signing. No one can predict the future, so it is understood your intentions with the property may change over time. If you bought it as a primary or second home and immediately switched it to a rental, then the lender could make the case that fraud existed at time of signing because your obvious intent was to use it as a rental.
So, the more time that passes between signing the second home rider and when you first rent the home out, would be a key factor in any dispute. Most of these riders have a one year waiting period, but, as we say in the tax world, it would be a case of "all the facts and circumstances".
I hope this helps.
Each lender has their own riders. No one in this open forum without reading the rider in question would be able to comment on any rental restrictions. The lender is looking for someone that will care for the house evidently. As you know, rental homes take more abuse, on average, than an owner lived in home.
The mortgage company wants you to be responsible first and foremost, make the payment every month, take care of the property etc. The documents up front are an attempt to prevent fraud, some true investors try and get a loan that states it is a 2nd home with no intention of living in the home.
Glad to answer any questions you might have.