Thank you all for providing some useful information.
I wanted to provide some updates after doing some research. There is an insurance called "Cancel For Any Reason (CFAR)." This type of insurance gives you up to 50% of reimbursement for any reason of cancellation. For example, CAA's CFAR costs about $150 per person for $6000 5 days trip. You can get $3000 back for any reason of cancellation, however, if your reason is under the insured risk (such as illness), you can get all $6000 back.
The reason that my trip costs a lot is because it is a business conference trip. The conference registration is about $1000 per person (nonrefundable). Both of my husband and I are the invited speakers so it costs us $2000 just for the registration out of $6000. All of the costs will be covered by our employer including the travel cancellation/interruption insurance. The destination is one of the most expensive countries so that is why the cost is high for the hotel (hotel is also nonrefundable through the conference rate).
However, if I can't go due to the citizenship exam/oath, the company will not cover the nonrefundable costs so the costs will be on me and my husband (my husband said that if I am not going to the business conference, he will not go either although his cost is also covered by our employer).
After doing all of the calculation, we have decided to book the refundable hotels and flight tickets (not through the conference website) which will cost about $8,000 in total. I think this is a safer option.
Hi
You have not provided dates of citizenship application and travel to help me answer this in a slightly better way. That said, it seems like you are still waiting for the citizenship test ( so I guess you should worry about this and not OATH).
From personal experience, I got my test date for 25 Jan 2018, and as it so happened I had business trip planned for that same week. All you have to do is keep checking your ECAS and then submit your travel proof online via the IRCC web form. I did this and they rescheduled my test with NO ISSUES at all.
I have also received the GCMS/ATIP notes which confirms that they received the webform submission. I had my test on 15 March 2018 and now waiting for oath.
If I were you I would not pay anything extra for tickets or insurance. I believe you are overthinking the process.. yes, IRCC is unpredictable but applying for citizenship is not supposed to be a hassle and IRCC understands that people have jobs and they may take business trips.
For further info, during the citizenship test/interview - they also ask you if you are travelling over the next 2-3 months so they dont schedule the Oath for those particular dates.
Hope this helps everyone. Certain people on this forum just like to make everything a super big deal as if it were death sentence hearing in Supreme Court instead of actually helping people. Please ignore them.