It's a common mistake to not include fonts. When you hand over data, it should always include all the necessary information - including the fonts that were used in the logo.
If a font is not included, it might be automatically replaced with another, etc. The logo would be printed wrongly, and a lot of money is lost.
To avoid such problems from the beginning, you should always transform all texts in the logo into paths. When the logo is finished, the text won't be changed anyway.
Don't forget to mind the licenses when using fonts. Check possible extra costs for fonts with the customer in advance.