Dear Yankexpat,
Thanks for your post!
The short answer to your question is that programs will not likely verify exact dates of your collegiate and post-collegiate XCs. Many schools will, however, verify that you did in fact particpate - hence their request for a contact person - and they may ask that contact person for a rough estimate of when you took part in the activity to ensure that this matches your claims.
Obviously, this isn't an exact science as your employment record or dates of education might be, so my advice is that you do the absolute best you can to get the dates right. If you are off by a matter of a week or two, this shouldn't be a problem. Of course if you fudge something by more than a matter of weeks (to artifically lengthen your dates), it could spell trouble for you during a check (should your contact person not corroborate the details), so again, do your best to be accurate.
For more information on background checks, see the following post:
https://blog.clearadmit.com/2007/01/admi ... nd-checks/
Best of luck,
Graham
