If access to the property is consistently denied, lease violations are enforced.

You can't deny based on non paycheck income source. 

Under most circumstances like this, I advise my clients to deny the application when there is no way  NOT to lose insurance coverage, but I advise my clients to first contact their insurance provider to inquire about any provisions in their policy that would alleviate this problem. 

I've tried to "help" by letting tenants in default get out of eviction and leave voluntarily and got left with trashed properties on multiple occassions.If your criteria says to deny an applicant. stick to the facts.

If I am also pre-qualified/approved with two other lenders, B and C, and lender A denies financing, can the seller see that I am approved with other lenders? 

If however you don't have good credit, the scenario is unique, or you are getting denied by several lenders, I would recommend working with a broker.

Now that source of income is a protected status in CO, landlords can't deny a tenant based on the applicant using a voucher so govt. subsidized renters can rent anywhere that they can find something they can afford.

Not perfect, and definitely should always do additional research, but we can't deny that it can be useful for ideas or questions like this.I'm still VERY new to REI.

If the loan is denied the lender will refund you this deposit. 

Thank you @Denis Ponder!