Help with replacing text

Is there any practical limit to the length of a string which can be used as an AppleScript text item delimiter? For instance, this appears to work on my OS 9.1 setup

set targetContent to "This is a simple string which has been created for test purposes only. The script is going to remove this last sentence." 
set removeThisText to " The script is going to remove this last sentence."
set oldTIDs to AppleScript's text item delimiters 
try 
set AppleScript's text item delimiters to removeThisText 
set cleanedText to every text item of targetContent 
set AppleScript's text item delimiters to oldTIDs 
on error 
set AppleScript's text item delimiters to oldTIDs 
end try
set cleanedText to cleanedText as text

Is this safe?
Rob J