Yes, if the transponder list is already full, then no more can be added, unless some useless ones are deleted to make room. However performing a blind search will only work if there is space for more transponders in the list, as it adds them where it had found a signal.
With a transponder list that is almost full, performing a blind scan will often exacerbate the problem by adding uneccessary and sometimes repeated transponders to the list.
Personally I would only use blind scan if I was feeling lazy,looking for feeds or a transponder change had not yet been updated on lyngsat, flysat, kingofsat etc.
EDIT, yes, I should have added in my previous post,
as long as there is sufficient transponder memory space available.
There is also the possibilty of clearing out unwanted transponders without having to think too much, by getting rid of H tps on 7W, and any eastern beam tps on 42E for example, as the dish isn't large enough to get them.
