Use of ROLLBACK

We have an application development group that has put together an application that primarily queries a database. While many read I/O's take place (no attempt has been made to optimize queries) the development group claims that they are not updating so I'll assume most of the writes could be attributed to things like hash joins, sorting, or grouping. The database is logged, unbuffered. Here's the question. For some reason, they coded the application to issue a ROLLBACK at the conclusion of a transaction. For example: Begin work; Select.. Select. Select. Rollback; This is not used because they wish to "change their mind" - a standard inquiry uses ROLLBACK. Where they actually want to save any data, they obviously use a commit. Off the top of my head I can't think that this is a very efficient way of releasing held locks. They claim it shouldn't make any difference because they didn't modify anything. Yet, like a mentioned above, I see 'write' I/O 's when I "onstat -u". An "onstat -p" doesn't show many rollbacks (relative to the Thoughts.comments.suggestions.