Wiktionary:Warning

The purpose of user warnings is to guide good-faith testers and dissuade bad-faith vandals. Issuing more than one warning level simultaneously serves no purpose, since they did not get the first warning before you escalated to the next resort.

Blocks are supposed to be prevent vandalism, not punish it. If the user stopped vandalizing some time ago, and their edit histories don't suggest a pattern of chronic vandalism, there's no need to warn or block them at all (although a welcome template might help future visits). Likewise, if a user is in the midst of an obviously bad-faith vandalism spree, there's no need to warn them before temporarily blocking them.

These templates are placed on user talk pages to warn a user against vandalism, convey a standardised message, or to place a standard boilerplate note at the top of a page. You are responsible for ensuring that the template's text is appropriate to the violation: if the template's tone isn't appropriate, don't use the template. They are not a formal system that you have to use: they are a shortcut to typing, nothing more. If you cannot find a template that says what you want to say then go ahead and say it normally.