Do you think the acceptance of gratuities by police is corruption? Should it be allowed? My Friends Think this is okay i say not it just not right.

Your definition of "gratuity" would be very helpful here. 
If by gratuity, you mean taking something extra (like money) at the end of performing a
service, then I agree that this borders on bribery, which is
unlawful.

On the other hand, many Starbucks, for example,
have the policy to serve free coffee to anyone in uniform.  I understand it was a
managerial decision unique to each store, but this was certainly the case at the two
Starbucks in Waco, TX.  If this is what you mean, then I do not see anything wrong with
this.  In fact, it is a win-win for both the company and the officer.  Officers get free
coffee, and Starbucks has a consistent and regular police presence.  This sends a
message to the neighborhood that Starbucks is attempting to promote safety as well as
thank services that largely go underpaid.  (I used to constantly ask for a teacher
discount to no avail...)