The .tmp files are processed by the AM agent; if you remove it, they definitely won't be processed.  Have you tried uninstalling and reinstalling the AM agent on an offending machine?  What version are you running?

The solution isn't to stop them from creating .tmp files, it's to get them to process the .tmp files.  I wonder, too, if AV is interfering.  We exclude Altiris directories from our AV.

This took a lot of digging but the outcome was favorable with a twist:

We came up with a fix to disable the invasive tmp files but found out that AppMetering should never be run on High-End workstations - meaning intensive I/O, process intensive or simulation or drafting workstations, engineering fpga development etc...

Unfortunately our environment is heavily involved with just these types of workstations.  I will get back within a week and document the fix and try to collaborate with Altiris SE about the AppMetering issue and tmp files.

Article ID: 48715

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Eugene's right, if you don't want to fix Application Metering, but just want to remove it entirely (and have), then this KB may apply to you:
https://kb.altiris.com/article.asp?article=48715&p=1