Is there some system imposed limit to the number of open forms?

Or, is there some performance-related limit to the number of open forms?

I have an application in which the user can easily create many open forms ... actually, since it is a "reporting" application, the user need never close any form, as he can "drill down" to a new form for more detail or revisit previous forms to "drill down" a different way.

So, it seems that some users will not be very tidy and and they will open forms and leave them around forever (much like the top of the desk in my office).

What I'm curious about is if I need to be attentive to clean up after such users, or whether I can just let them be.

Thanks