Please clarify what do you mean with "default jetways", because default jetways are automatically removed when installing GSX or (after a sim update) with the GSX Control Panel, without any need to create an Exclusion file.
If with "default jetways", instead of default jetways, you mean "the jetways the scenery originally came with", this changes a lot depending if the jetways the scenery originally came with were made using the standard system (so they operate with CTRL+J), or they were made with SODE.
- If they are made using the standard system, it's not possible they would reappear by enabling SODE, since SODE has no way to make standard jetway appear or disappear
- If they are made with SODE, you are not supposed or required to create a GSX Exclusion file to remove them. Instead, you must remove their XML file in the %PROGRAMDATA%\12bpilot\SODE\XML folder, that's the only way to remove SODE jetways.