Will an admissions reader call your recommender?

For a third party, supplemental letter of recommendation (i.e., an employer, coach, mentor), is it common for an admissions reader to give them a call to confirm their comments/ask clarifying questions?

I ask because mine is from my Congresswoman (who I know on a personal level, and I intern for, so no-it’s not just a crappy template letter, before you all go off on me) and she asked me whether or not she should put her cell phone number, a very private number, because they obviously cannot contact her directly through her offices.

Thanks,
DP

99% of the time, there would not be a reason to reach back to LOR writer. And if the occasion arose, you can be pretty sure that the person calling would do so for professional reasons only-- to ask for clarification. If your writer doesn’t mind, I think it’d be better to include that cell number.