Unique Identifier with Extra Characters Still Matching in Select
The implicit conversion also works if the value is enclosed in curly brackets {...}. 

If you add those in the query the implicit conversion will fail if the original value is too long because the last } ends up in the wrong place.

select * 
from some_table 
where uuid = '{'+'7DA26ECB-D599-4469-91D4-F9136EC0B4E8'+'}'


If you try the convert 

SELECT CONVERT(UNIQUEIDENTIFIER, '{'+'7DA26ECB-D599-4469-91D4-F9136EC0B4E8EXTRACHARS'+'}');


you get

Msg 8169, Level 16, State 2, Line 1
Conversion failed when converting from a character string to uniqueidentifier.