Within reason, I agree, but, it should take substantial effort to do so.
Blindsense requires line of effect, so, if a PC can come up with a way to sneak up on a dragon staying out of it's LoE, then sure, I'll go for it, but, just moving silently towards it in the open, come up with a better idea.
Blindsense requires line of effect, so, if a PC can come up with a way to sneak up on a dragon staying out of it's LoE, then sure, I'll go for it, but, just moving silently towards it in the open, come up with a better idea.