Regarding the list of "high risk" countries subject to processing holds..

My in-laws are green card holders from Russia and have been in the US for 15 years continuously. We were planning on submitting their N-400s in June but are now worried that even if they pass their civics test, they won't be granted citizenship on account of some unforeseen delay regarding swearing in ceremonies, etc. Is this a legitimate concern? They are 80 and 81 years old respectively, have not left the country and have no criminal record.