It doesn't matter whether the it's bottom tested or not. For example, you can break out of bottom tested loops in Visual Basic.

Also, consider

local $\="\n";
print('a');
{
   print('b');
   last;
   print('c');
}
print('d');
[download]

a
b
d
[download]

versus

local $\="\n";
print('a');
do {
   print('b');
   last;
   print('c');
};
print('d');
[download]

a
b
Can't "last" outside a loop block at a.pl line 5.
[download]

See bellaire's post for the real reason.