If they are out for more than a quarter hour the site should remove them from the tournament.
In paid tournaments I think, that would be to harsh. Its already not exactly a great strategy to be blinded away, and if someone has to go for life related reason or lose his internet, its fair to me, that he can make it as far, as his stack will last. In freerolls however I think, it would be fair to remove inactive players. If you dont have time to play a freeroll, then dont register. Pretty much as simple as that.
I also dont understand, why there need to be late registration in freerolls. Its not like, the site earn any more money that way or can create a larger pricepool. If someone did not manage to register, good for the players, who did, and if he has a ticket, he can just play the next freeroll. I absolutely love, that the Cardschat freerolls on
pokerstars have no late registration. Be there on time, or dont go there at all.