Well then how has Tobirama been teleporting??, except ofcourse he can teleport without seals, he doesn't have kunais yet he teleports with Obito
here:
You must be registered for see images
So if he didn't place his seal somewhere, how did he teleport with Obito??
and then there's
here:
You must be registered for see images
He uses FTG to get Minato, Hiruzen Emma and Naruto out of danger, so if he didn't have a seal placed where he took them to, how did he do it??
so it's either Tobirama can place marks on objects, or he can use FTG without seals.. I think the answer is quite obvious