[racket] (Practical) Limits of Apply?

Hello all,

I recently encountered some library code of the form

(apply append list-of-lists)

where list-of-lists could be essentially arbitrarily long (i.e. list-of-lists came from clients of the library, and therefore could be anything).  I didn't try to break it, but it made me a little nervous---I know that other Schemes have limits on the number of arguments that can come through apply.  In practice, should I be worried about using apply on, say, 1M-element argument lists?  

Thanks,
Will