It appears as though this question actually concerns weighing the viability of a business policy.
In its simplest form:
"Does the value of making our application available as a trial download outweigh the potential detriment of letting competitors have the files to reverse-engineer it?"
As I see it, this question (in its simplest form) does not have a practical answer - there are too many variables to factor in.
- Is the software open or closed source?
- Could analysis of the software expose any vulnerabilities or proprietary resources which malicious users could abuse?
- Would an online demo be sufficient to let users determine whether the software will solve the need they are shopping to fill?
... et cetera.
I would not consider business policy questions appropriate to Pro Webmasters or UX: OnStartups would be a better fit if you can revise the question to accommodate the quality guidelines there.
Be wary of subjective qualifiers like "is it reasonable" - a good question can be answered with factual information which leaves little room for opinion.