Did a bit of research and think I found out how eBay is verifying our sin numbers. I could be wrong.
The first digit determines the province:
First Digit When It’s Used
1 For those born or residing in New Brunswick, Newfoundland, Prince Edward Island, or Nova Scotia
2 For those born or residing in Quebec
3 For those born or residing in Quebec
4 For those born or residing in Ontario
5 For those born or residing in Ontario
6 For those born or residing in Alberta, Manitoba, Saskatchewan, Nunavut, or the Northwest Territories
7 For those born or residing in British Columbia or the Yukon
8 Never used
9 For those who immigrated to Canada and temporary workers
0 Never used
Using some quick math, you can verify your Social Insurance Number. The Luhn algorithm follows a simple procedure to check whether it’s correct.
EX: JANE DOE, SIN # 844 871 988
* For the purpose of this article, we are using a SIN number starting with eight (a non-valid number).
1. Line up the SIN number against this exact numeral: 121 212 121
2. Take each column of digits and multiply them one by one.
8 4 4 8 7 1 9 8 8
1 2 1 2 1 2 1 2 1
8 8 4 7* 7 2 9 7* 8
*If you get a two-digit result, simply add the digits together (Ex. 8 x 2 = 16 → 1 + 6 = 7)
3. Next, take the sum of all the digits: 8+8+4+7+7+2+9 +7+8 = 60
If the sum is divisible by ten, the number can be a true SIN, so based on the formula, it could be valid. However, since it starts with 8, we know that it is not valid.
Found here:
https://loanscanada.ca/money/what-is...ce-number-sin/
Can also use this site to generate a valid sin or check the validity of a sin:
https://www.⊗⊗⊗⊗namegenerator.com/so...nce-number.php
Maybe this info useful to those making Canadian stealth eBay accounts.
How eBay verifies SIN number 
when asked for ID - it is possible to operate decently without the request but I haven't needed to create new accounts in awhile so just working with old ones
