[donkehote]

Originally Posted by cgmv123

Yes, that would be the concern.

What rule disallows thermal paste? Sticking chemicals on the outside of electronics is modification? Would the same rule disallow Velcro attachment, or labels being applied to speed controllers? Both of those use chemical compounds applied to the heat sink causing different operating conditions.
Your post reminds me of the bumper pool noodle tape issue from last year.

Some things don't need regulating IMHO.