At our department - yes.it is a common practice for LEOs to check for a valid TDL, if the driver forgot it.
If someone has a CHL we will find out when we run their DL. If they have neither with them we will find out when we run a subject check. There is no set policy or procedure at our department as to what we "should" do if this occurs. This is not one of those few offenses where the law dictates that you "shall arrest" the individual, so there is tremendous leeway for the officer. That being said, with 3,000 officers on our department you could have a wide range of responses. Me personally - it would depend upon the reason for initial contact and how the individual responded....what is your practice when the same thing happens with a CHL holder...
Rule #1 - don't lie to the police. If you forgot your CHL and have your gun with you, just tell the officer that you left your license at home. Let's say you didn't have your CHL and got stopped for whatever reason. If you get caught up spinning some type of tale you are probably not going to like the results.
The good thing is that CHL holders are pretty good about not forgetting their licenses so this is probably a very small occurrence. I, nor any officer I know have ever had this happen.