Alamo or Hertz credit card holds if redeeming air miles?

[BelleTink]

Does anyone know if Alamo puts a hold on your credit card if the rental is "pre-paid" with airline mileage points? And if they do, how much? I haven't used Alamo in years, and never via air miles.

Or same question for Hertz, they're my other option to use my points.

Thanks!